# Newton's law of motion Questions and Answers

Physics
Newton's law of motion
A 20.0-kg box rests on a table. (a) What is the weight of the box and the normal force acting on it? (b) A 10.0-kg box is placed on top of the 20.0-kg box, as shown in Fig. 4-43. Determine the normal force that the table exerts on the 20.0-kg box and the normal force that the 20.0-kg box exerts on the 10.0-kg box.
Physics
Newton's law of motion
One 3.2-kg paint bucket is hanging by a massless cord from another 3.2-kg paint bucket, also hanging by a mass-less cord, as shown in Fig. 4-49. (a) If the buckets are at rest, what is the tension in each cord? (b) If the two buckets are pulled upward with an acceleration of 1.25 m/s² by the upper cord, calculate the tension in each cord.
Physics
Newton's law of motion
A 975-kg sports car (including driver) crosses the rounded top of a hill (radius = 88.0 m) at 18.0 m/s. Determine (a) the normal force exerted by the road on the car, (b) the normal force exerted by the car on the 62.0-kg driver, and (c) the car speed at which the normal force on the driver equals zero.
Physics
Newton's law of motion
Moments after making the dreaded decision to jump out the door of the airplane, Darin's 75.5-kg body experiences +128 N of air resistance upward. Determine Darin's acceleration (in m/s2) at this instant in time. Hint: Your answer will be negative since he is falling (i.e., his acceleration is still in the down direction).
Physics
Newton's law of motion
Which choice is a valid way to construct a motion diagram? Add together the average speeds of the various objects in motion. Take a series of photographs at equal time intervals of a moving object, perpendicular to the direction of motion; overlay the images to see how the position changes with time. Draw vectors to represent the speeds involved. Add vectors in a head-to-tail manner to determine the resultant vector.
Physics
Newton's law of motion
A net force of 25 newtons is applied horizontally to a 6.25-kilogram block resting on a table. What is the magnitude of the acceleration of the block? 0.0 meter per second squared 0.40 meter per second squared 0.26 meter per second squared 2.5 meter per second squared
Physics
Newton's law of motion
A 1.5-kilogram lab cart is accelerated uniformly from rest to a speed of 2.0 meters per second in 1.0 second. What is the magnitude of the force producing this acceleration? * O 0.70 N O 1.5 N 3.0 N O 6.0 N
Physics
Newton's law of motion
One end of an ideal spring is fixed at point O and other end is attached to a small disc of mass m which is given an initial velocity vo perpendicular to its length on a smooth horizontal surface. If the maximum elongation in spring is l₀/4 then (l₀ = natural length and k = stiffness of spring).
Physics
Newton's law of motion
A man of weight W= 160 N holds one end of a rope that passes over a pulley vertically above his head and to the other end of which is attached a weight Q = 120 N. Find the force with which the man's feet press against the floor. Ans. 40 N
Physics
Newton's law of motion
Suppose a 500 N force is applied to a 75 kg student sitting on a chair with wheels. As the student is accelerating to the "right", he encounters a frictional force of 75 N.. a. Draw a free body diagramanduse vector addition to show the net force during his acceleration. a. Calculate the acceleration.
Physics
Newton's law of motion
The gravitational field constant and falling objects on Mars. On Mars, the gravitational field constant is g = 3.7 N/kg. a. How much would a 2.0 kg mass weigh on Mars? b. If this object was allowed to fall for 4.0 s, what would be the new velocity of the rock, assuming no resistance with the atmosphere of Mars? c. What distance would the object fall assuming no atmospheric resistance? d. When the object does encounter the atmosphere of Mars and reaches terminal velocity, what would the free-body diagram look like? Please label the forces involved.
Physics
Newton's law of motion
The physics of a baseball player and kinetic friction. A baseball player of mass 80.0 kg slides into home base. The coefficient of kinetic friction between the player and the ground is 0.610. a. What is the magnitude of the frictional force? (In solving this part of the question draw a free- body diagram with all of the forces labelled. Use a rectangle to represent the baseball player. Also, assume the player is moving to the right while sliding.) b. If the player comes to rest after 1.5 s, what must have been the initial speed of the player?
Physics
Newton's law of motion
One of our foster cats Jill had a mass of 3.6 kg, her four babies when adopted were about 0.5 kg each. a. Who was easier to pick up (assume they were sleeping), Jill or one of her babies, explain in terms of Newton's 1st Law?. b. If Jill pushes down on the floor with a force of 45N, what does the floor do? d. What is Jill's apparent weight on an elevator moving down at a rate of 0.5 m/s²? e. I had to take both Jill and her kittens to showings at the local pet store, I found it easier to put the carriers into a shopping cart and push them from the car rather than trying to carry all of them at once. The total mass being pushed was about 25 kg. If the cart handle makes an angle of 25° above the ground, and I am pushing at a constant velocity of 100N, what is the frictional force of the ground?
Physics
Newton's law of motion
part 1 of 3 A boat moves through the water with two forces acting on it. One is a 2022 N forward push by the motor on the propeller, and the other is an 1807 N resistive force due to the water around the bow. What is the acceleration of the 1066 kg boat? Answer in units of m/s². Answer in units of m/s^2 part 2 of 3 If it starts from rest, how far will it move in 17.7 s? Answer in units of m. Answer in units of m part 3 of 3 What will its velocity be at the end of this time interval? Answer in units of m/s. Answer in units of m/s
Physics
Newton's law of motion
In which situation does the momentum of a tennis ball change the most? a.It hits the racket and stops. b.It hits the racket and flies off in the opposite direction. c.It misses the racket and continues moving. d. It hits the net and stops
Physics
Newton's law of motion
Which of the following statements is true of springs? a. A stiffer spring has a higher spring constant. b. Extension and compression are equivalent except for direction. c. Restoring force is proportional to displacement from equilibrium. d. Simple Harmonic Motion is a natural consequence of their properties. e. Stored energy is directly proportional to displacement from equilibrium.
Physics
Newton's law of motion
Solve the problem below by first drawing a free-body diagram, identify which Newton's Laws are being applied and calculate the applied force. Keontae pushes a go-cart causing the cart to accelerate from 0 m/s to 8.5 m/s in 5 seconds. The mass of the cart is 125 kg and the coefficient of friction is 0.55. Calculate Keontae's applied force.
Physics
Newton's law of motion
ball is thrown at a 60.0° angle above the horizontal across level ground. It is thrown from a height of 2.00 m above the ground with a speed of 20.0 m/s and experiences no appreciable air resistance. The time the ball remains in the air before striking the ground is closest to 3.07 s. 3.64 s. 3.53 s. 16.2 s. 3.32 s.
Physics
Newton's law of motion
A 5 kg block is pulled across a table by a horizontal force of 40 N with a frictional force of 8 N opposing the motion. Calculate the acceleration of the object.
Physics
Newton's law of motion
A child bounces a 48 g superball on the side-walk. The velocity change of the superball is from 22 m/s downward to 19 m/s upward. If the contact time with the sidewalk is 1/800 s, what is the magnitude of the average force exerted on the superball by the sidewalk? Answer in units of N.
Physics
Newton's law of motion
A large, moving truck crashes into a small parked car. How do the magnitudes of the impulses and the forces on each vehicle compare during the collision? A. The truck experiences less force and less impulse. B. The truck experiences equal force and equal impulse. C. The truck experiences less force but more impulse. D. The truck experiences more force but less impulse.
Physics
Newton's law of motion
Egg A is dropped from a height of 1m onto the floor. Egg B is dropped from a height of 1m into a bucket of water. Which statement correctly describes why Egg B does not break? A. Egg B experiences less force over a shorter time B. Egg B experiences greater force over a longer time C. Egg B experiences a greater force over a shorter time D. Egg B experiences less force over a longer time
Physics
Newton's law of motion
A bullet with a mass of 5.00 10^-13 kg is loaded into a gun. The loaded gun has a mass of 0.52 kg. The bullet is fired, causing the empty gun to recoil at a speed of 2.1 m/s. What is the speed of the bullet? A. 48 m/s B. 360 m/s C. 220 m/s D. 120 m/s
Physics
Newton's law of motion
A 2,069 kg vehicle exerts 173,227 newtons of force during a sudden stop. If the stop takes 0.272 seconds, what is the vehicle's change in velocity (Av)? Round your answer to the nearest 0.1. Do not add units. Since you are looking for Au as a whole piece, you can treat it as a single variable in your equation.
Physics
Newton's law of motion
A 4.3 kg bucket of water is raised from a well by a rope. The acceleration of gravity is 9.81 m/s². If the upward acceleration of the bucket is 4.4 m/s2, find the force exerted by the rope on the bucket of water. Answer in units of N.
Physics
Newton's law of motion
A 2.00 kg block is in equilibrium on an incline of 20.3°. The acceleration of gravity is 9.81 m/s². What is Fn of the incline on the block? Answer in units of N.
Physics
Newton's law of motion
The physics of a swimming duck and net force. A duck has a mass of 2.5 kg. As the duck paddles, a force of 0.10 N acts on it in a direction due east. In addition, the current of the water exerts a force of 0.20 N in a direction of 52° south of east. a. Determine the net force on the duck. b. Determine the acceleration of the duck.
Physics
Newton's law of motion
A cue stick hits a cue ball with an average force of 34.0 N for a duration of 0.0280 s. If the mass of the ball is 0.160 kg, how fast is it moving after being struck?
Physics
Newton's law of motion
Coyote (m. = 14.7 kg) is about to try out his new rocket sled (m. = 50.9 kg), which can produce a thrust of 1850 N. What is the value of the normal force, Fy. exerted upwards by the road?
Physics
Newton's law of motion
Joe pushes down the length of the handle of a 12.8 kg lawn spreader. The handle makes an angle of 45.4° with the horizontal. Joe wishes to accelerate the spreader from rest to 1.33 m/s in 1.6 s. What force must Joe apply to the handle? Answer in units of N.
Physics
Newton's law of motion
What minimum value must the coefficient of static friction between the hill and ball surfaces have for no slipping to occur?
Physics
Newton's law of motion
A student pulls a box of books of total mass 40.0 kg on a smooth horizontal floor with a 100 N force in a direction of 37° above the horizontal surface. (a) The magnitude of the normal force on the box by the floor is (1) greater than, (2) equal to, or (3) less than the weight of the box. Explain. (b) What are the magnitudes of the acceleration of the box and the normal force on the box by the floor?
Physics
Newton's law of motion
A string pulls on a rock, causing it to move in a horizontal circle. The rock's mass is 2.56 kg, the string length is 2.81 m, and the centripetal force is 10.57 N. What is the rock's speed?
Physics
Newton's law of motion
Abby, who has a mass of 45.0 kg, is riding at 40.0 m/s in her red sports car when she must suddenly slam on the brakesto avoid hitting a deer crossing the road. She strikes the air bag, that brings her body to a stop in 0.500 s. Whataverage force does the seat belt exert on her?What if Abby had not been wearing her seat belt and not had an air bag, then the windshield would have stopped herhead in 0.002 s. What average force would the windshield have exerted on her? 1. Solve for force in each scenario. 2. Explain the significance of time on the overall force and link to Newton's first and second laws.
Physics
Newton's law of motion
A 9.0 kg object experiences an acceleration of 1.2 m/s². (a) What is the magnitude of the resultant force acting on it (in N)? (b) If this same force is applied to a 5.4 kg object, what is the magnitude of the acceleration (in m/s²)?
Physics
Newton's law of motion
A man claims he can safely hold on to a 13.4-kg child in a head-on collision with a relative speed of 119-mi/h lasting for 0.10 s as long as he has his seat belt on. (a) Find the magnitude of the average force needed to hold onto the child. (b) Based on the result to part (a), is the man's claim valid? (c) What does the answer to this problem say about laws requiring the use of proper safety devices such as seat belts and special toddler seats?