Newton's law of motion Questions and Answers

On vacation, your 1400-kg car pulls a 590-kg trailer away from a stoplight with an acceleration of 1.20 m/s². You may want to review

Three men were trying to pull a tree stump out of the ground. The first man was pulling with a force of 100 N to the North. The second man was pulling with a force of 75 N at an angle of 45 degrees North of East. The third man was pulling at 75 N at an angle of 45 degrees North of West. What resultant force is being applied to the tree stump?

A sled of 6.0 kg mass is moving along a smooth, horizontal ice surface with a velocity of v. A force of 36 N is applied to the sled in its direction of motion, increasing its velocity to 2v, while it moves 10 m. Find a) the sled's original velocity, v0 (6.3 m/s) b) the length of time that the force acted (1.1 s)

A 0.46 kg ball moving in a circle at the end of a string has a centripetal acceleration of 7 m/s² (a) What is the magnitude of the centripetal force exerted by the string on the ball to produce this acceleration?

Conner claims he can throw a football 50.0 m. a. What angle should he throw the ball to achieve maximum distance? b. If he throws the ball at that angle with an initial velocity of 21.5 m/s, will he reach 50 m?

For a certain interval of time, an object is acted on by a constant non-zero force. Which of the following statements is true for this interval of time? (Select all that apply.) The object is moving with constant velocity. The object's velocity can only increase. The object is at rest. The object is accelerating. The object's velocity changes.

On his way to class, a student on a skateboard is accelerating on a downhill stretch. Which of the following statements is true? (Select all that apply.) The skateboarder is subjected to a net external force in the direction of motion. The skateboarder is moving in the direction of the net force. The skateboarder's acceleration is perpendicular to the net force. The skateboarder's acceleration is in the direction of the net force.

The specialty of an athlete on the women's track team is the pole vault. She has a mass of 60 kg and her approach speed is 8.1 m/s. When she is directly above the bar, her speed is 1.5 m/s. Neglecting air resistance and any energy absorbed by the pole, determine the amount(in m) she has raised herself as she crosses the bar.

A man does 4,510 J of work in the process of pushing his 3.00 x 10^3 kg truck from rest to a speed of v, over a distance of 28.0 m. Neglecting friction between truck and road, determine the following. (a) the speed v (in m/s) (b) the horizontal force exerted on the truck (in N)

At the presentation ceremony, a championship bowler is presented a 1.70-kg trophy which he holds at arm's length, a distance of 0.655 m from his shoulder joint. (a) Determine the torque (in N-m) the trophy exerts about the shoulder joint when his arm is horizontal(Enter the magnitude only.) (b) Determin. e the torque (in N-m) the trophy exerts about the shoulder joint when his arm is at an angle of 17.0° below the horizontal. (Enter the magnitude only.)

The world record for diving was set August 4, 2015 by the Swiss diver of Brazilian descent, Lazaro "Laso" Schaller. His dive was 58.8m (192 feet and 10 inches, higher than the Tower of Pisa) and exceeded a speed of 120 km/h (74.5 mph) at his entry into the water. How fast was Laso falling 3 seconds into his dive? Ignore air resistance.

An upward force of 32 N is applied via a string to lift a ball with a mass of 7.9 kg. (a) What is the net force acting on the ball? (b) What is the acceleration of the ball? Assume up is positive, down is negative. Use g = 9.8 m/s²

3) A typical game at the physics amusement park has you push a puck up a long, frictionless ramp. You can win a "get out of homework free" card if the puck, at its highest point, comes to within 10 cm of the end of the ramp without going off. You give the puck a push, releasing it with a speed of 5.0 m/s (along the incline) when the puck is 8.5 m from the end of the ramp. The puck's speed after traveling 3.0 m up the ramp is 4.0 m/s. Do you win the card? Can you determine the angle of incline of the ramp?

(17%) Problem 2: A horizontal force, F, 75 N, and a force, F₂= 14.5 N acting at an angle of 0 to the horizontal, are applied to a block of mass m 4.5 kg. The coefficient of kinetic friction between the block and the surface is µk = 0.2. The block is moving to the right. Randomized Variables F₁ = 75 N F₂-14.5 N m = 4.5 kg

A ball rolls off a table with a horizontal velocity of 4 m/s. If it takes 0.5 s to reach the floor: (a) What is the vertical component of the ball's velocity just before it hits the floor? (b) What is the horizontal component of the ball's velocity just before it hits the floor? Use g = 10 m/s²

5) During the balancing act experiment 200gram mass is attached to 0.20m (20cm) mark and an unknown mass is attached to 0.75 cm mark. The meter stick is 150 grams and the point of rotation is at 0.60m (60cm) mark. A) Find the Torque at the left of the point of rotation. B) What should be the unknown mass so that the system is in the equilibrium. C) What is the force exerted by the support?

A car is travelling with uniform motion and has a total frictional resistance of 2.8 x 10^3 N acting in the direction opposite to the motion of the car. From this information, we know that the force acting on the car in the direction of the motion is: a) much greater than 2.8 x 10^3 N b) exactly equal to 2.8 x 10^3 N c) much less than 2.8 x 10^3 N d) less than 2.8 x 10^3 N e) greater than 2.8 x 10^3 N

7. A slanted roof rises at 35° above the horizontal, and the straight-line distance from the top of the roof to the bottom edge is 4.5 m. The roof is covered with ice, so it offers no friction to objects sliding on it. A piece of ice at the top suddenly breaks loose and begins to slide down from rest. (a) How long will it take for the ice to reach the bottom edge of the roof? (b) How fast will the ice be traveling just as it reaches the bottom edge?

11. The curved section of a horizontal highway is a circular unbanked arc of radius 740 m. If the coefficient of static friction between this roadway and typical tires is 0.40, what would be the maximum safe driving speed for this horizontal curved section of highway? 48 m/s 46 m/s 54 m/s 52 m/s 50 m/s

A soccer goalkeeper kicks the ball with an average force of 1100 N during 0.012 s. What is the magnitude of the impulse delivered to the ball? 92,000 kg m/s 13 kg. m/s 1.1 x 10^-5 kg. m/s 170 kg. m/s

A musician applies a horizontal force of 17 N [W] to an instrument case of mass 5.1kg. The case slides across a table with an acceleration of 0.39m/s² [W]. What is the coefficient of kinetic friction between the case and the table?

A baseball approaches home plate at a speed of 46.0 m/s, moving horizontally just before being hit by a bat. The batter hits a pop-up such that after hitting the bat, the baseball is moving at 60.0 m/s straight up. The ball has a mass of 145 g and is in contact with the bat for 1.60 ms. What is the average vector force the ball exerts on the bat during their interaction? (Let the +x-direction be in the initial direction of motion, and the +y-direction be up.) F on bat N

2. A parent pulls a toboggan with three children at a constant velocity for 38 m along a horizontal snow-covered trail. The total mass of the children and the toboggan is 66 kg. The force the parent exerts is 58 N [18° above the horizontal]. (a) Draw an FBD of the toboggan, and determine the magnitude of the normal force and the coefficient of kinetic friction. [FN=642N μk=0.086] (b) Determine the work done on the toboggan by kinetic friction. [-2097]] (c) List three forces, or components of forces, that do zero work on the toboggan. [Weight, FN, Fsine] (d) How much work does the parent do on the toboggan in pulling it the first 25 m? [+2097]]

(8c5p26) A car traveling at 67 km/h hits a bridge abutment. A passenger in the car moves forward a distance of 63 cm (with respect to the road) while being brought to rest by an inflated air bag. What magnitude of force (assumed constant) acts on the passenger's upper torso, which has a mass of 37 kg?

1. A very thoughtful physics student takes her younger sibling to the arcade to play skeeball. She estimates the mass of the skee ball to be about 0.5 kg and the height of the fifty-point ring to be about 1 m above the position from which the ball is released. a. How much gravitational potential energy will the ball have if it hits the fifty-point ring at the highest point? b. How much kinetic energy does the ball need at its release to reach the highest point? c. At what velocity must the ball be released to reach the highest point? d. The student's sibling uses a radar gun to determine how fast she releases the ball, and it is exactly the speed she calculated to reach the 1 m height. However, the ball lands in the thirty-point ring, which is 0.8 m above the release point. How much energy is lost to friction if the ball only reaches 0.8 m instead of 1 m?

Two people are pushing a 20 kg box on an ice skating rink on opposite sides. One person is pushing with a 200 N force from the left side, while the other is pushing with a 250 N force from the right side. What is the acceleration of the box? Draw a free body diagram to illustrate the forces acting on the box.

51. (II) What will a spring scale read for the weight of a 58.0-kg woman in an elevator that moves (a) upward with constant speed 5.0 m/s, (b) downward with constant speed 5.0 m/s, (c) with an upward acceleration 0.23 g, (d) with a downward acceleration 0.23 g, and (e) in free fall?

A professional baseball pitcher can project a baseball at a speed as high as 37.0 m/s. (a) If air resistance can be ignored, how high (in m) would a baseball launched at this speed rise if projected straight up? (b) How long would the baseball be in the air (in s)?

A solid ball is released from rest and slides down a hillside that slopes downward at an angle theta from the horizontal. What minimum value must the coefficient of static friction between the hill and ball surfaces have for no slipping to occur?

One end of a uniform meter stick is placed against a vertical wall. The other end is held by a lightweight cord that makes an angle 0 with the stick. The coefficient of static friction between the end of the meter stick and the wall is 0.35. What is the maximum value the angle 0 can have if the stick is to remain in equilibrium?

(a) The 2 kg wood box in the Figure above on the left slides up a vertical wood wall while you push on it at a 45° angle. The coefficient of kinetic friction for wood on wood is = 0.2. What magnitude force Fpush should you apply to cause the box to slide up at a constant speed? Recall that constant speed means a = 0 m/sec². Answer: 34.6 N. (b) Let's re-do part (a), but with the box now sliding down the vertical wood wall while you push on it at a 45° angle. # is still μ = 0.2. What magnitude force Fpush should you apply to cause the box to slide down at a constant speed? Recall that constant speed means a = 0 m/sec². Answer: 23.1 N.

A very light ideal spring of spring constant (force constant) 2.5 N/cm is 15 cm long when nothing is attached to it. It is now used to pull horizontally on a 12.5-kg box on a perfectly smooth horizontal floor. You observe that the box starts from rest and moves 96 cm during the first 1.6 s of its motion with constant acceleration. How long is the spring during this motion?

A typical meteor that hits the earth's upper atmosphere has a mass of only 2.5 g, about the same as a penny, but it is moving at an impressive 40.0 km/s. As the meteor slows, the resulting thermal energy makes a glowing streak across the sky, a shooting star. The small mass packs a surprising punch. At what speed would a 900 kg compact car need to move to have the same kinetic energy? Assume all quantities are given to two significant figures. Give your answer in m/s.

A bolt drops from the ceiling of a moving train car that is accelerating northward at a rate of 3.96 m/s². (a) What is the acceleration of the bolt relative to the train car? m/s² southward and m/s² downward (b) What is the acceleration of the bolt relative to the Earth? m/s² downward (c) Describe the trajectory of the bolt as seen by an observer fixed on the Earth.

A Ferris wheel has radius 5.0 m and makes one revolution every 8.0 s with uniform rotation. A person who normally weighs 670 N is sitting on one of the benches attached at the rim of the wheel. What is the apparent weight (the normal force exerted on her by the bench) of the person as she passes through the highest point of her motion?

A clay ball (mass = 0.25kg) has a rightward momentum of +1.75 kg-m/s. A second clay ball (mass = 0.25 kg) has a leftward momentum of -1.75 kg⋅m/s. The two collide, stick together, and come to a complete stop after the collision.

On its own, a tow truck has a maximum acceleration of 3.0 m/s². What will be its maximum acceleration when the truck is using a light horizontal chain to tow a bus of twice its own mass? A. 1.0 m/s² B. 1.5 m/s² C. 2.5 m/s² D. 2.0 m/s²

A 50-kg box is being pushed along a horizontal surface. The coefficient of static friction between th the ground is 0.65, and the coefficient of kinetic friction is 0.35. What horizontal force must be exen box for it to accelerate at 1.2 m/s²? A. 490 N B. 230 N C. 170 N D. 60 N E. 120 N

While flying horizontally in an airplane, you notice that a string dangling from the overhead luggage compartment hangs at rest at 15° away from the vertical toward the front of the plane. Using this observation, you can conclude that the airplane is accelerating forward. moving backward. not accelerating because the string is at rest. O moving forward. accelerating backward.

A catcher stops a 0.15-kg ball traveling at 40 m/s in a distance of 20 cm. What is the magnitude of the average force that the ball exerts against his glove?

A net force of 125 N is applied to a certain object. As a result, the object accelerates with an acceleration of 24.0 m/s2. The mass of the object is 144 kg. 5.21 kg. 3000 kg. 2880 kg. 0.200 kg.

A 958-N rocket is coming in for a vertical landing. It starts with a downward speed of 25 m/s and must reduce its speed to 0 m/s in 8.0 s for the final landing. (a) During this landing maneuver, what must be the thrust due to the rocket's engines? (b) What must be the direction of the engine thrust force?

A locomotive is pulling 9 freight cars, each of which is loaded with the same weight. The mass of each loaded car is 37,000 kg, and we can neglect friction on these 9 cars. If the train is accelerating forward at 0.81 m/s²2² on a level track, what is the tension in the coupling between the second and third cars? (The car nearest the locomotive is counted as the first car.)

A tightrope walker walks across a 30-m long wire tied between two poles. The center of the wire is displace vertically downward by 1.0 m when he is halfway across. If the tension in both halves of the wire at this poin is 6294 N, what is the mass of the tightrope walker? Neglect the mass of the wire. A. 85 kg B. 91 kg C. 43 kg D. 74 kg

An object is being acted upon by three forces and moves with a constant velocity. One force is 60 N along the +x-axis, the second is 75 N along a direction making a counterclockwise angle of 150° with the +x-axis. (a) What is the magnitude of the third force? (b) What is the direction of the third force, measured clockwise from the +x-axis?

A 10-kg object is hanging by a very light wire in an elevator that is traveling upward. The tension in the rope is measured to be 75 N. What are the magnitude and direction of the acceleration of the elevator?

A 25 N block is lowered 1.2 m by a 20 N force. a. Draw a free-body diagram of the forces acting on the block. b. How much work does the force of gravity do on the box? Is this work positive or negative? c. How much work does the applied force do on the box? Is this work positive or negative?

A box hangs from a string that runs over a pulley and back to where a second box hangs. Select all the following that apply A) weight = mg, pulling straight down on both boxes B) the normal force, pushing straight up on both boxes C) the string pulling to the right D) friction resisting the motion, pulling to the left E) the tension in the string pulling straight up on both boxes F) the tension in the string pulling straight up only on the heavier box

A massive block is being pulled along a horizontal frictionless surface by a constant continuously changing direction moving at constant velocity moving with a constant nonzero acceleration moving with continuously increasing acceleration

The mass of a rocket decreases as it burns through its fuel. If the rocket engine produces constant force (thrust), how does the acceleration of the rocket change over time? A. It does not change. B. It increases. C. It decreases.