# Center of mass and momentum Questions and Answers

Physics

Center of mass and momentumA pole is planted into the ground at a 38⁰ angle. At the end of the pole is a 500 N pot. What force would need to be added to the pole in the Y-direction to maintain mechanical equilibrium?

Physics

Center of mass and momentumWhat is the moment of inertia of a uniform solid cylinder about its central axis of diameter d = 0.190 m, and total mass M = 1.65 kg? Show your work.

Physics

Center of mass and momentumTwo train cars are coupled together, traveling together on a straight level track with a velocity of 1.50 m/s to the right. The leading Car A has a mass of 5,000 kg, while the trailing Car Bhas a mass of 12,000 kg. (Assume 3 significant figures on all masses.) A small explosion suddenly separates the two cars. Afterward, Car A has a velocity of 2.50 m/s to the right. Ignore all external friction on the train cars.
What is the net impulse received by Car A, in kg-m/s? ________ kg-m/s Enter a POSITIVE value for rightward, or NEGATIVE value for leftward.

Physics

Center of mass and momentumOn a frictionless horizontal floor, two objects collide. Object A, which is moving in a velocity of 72 m/s, is 7 times of object B, which has a velocity of 40 m/s. Object A moves to the right while object B moves to the left. What is the velocity of the resulting combined mass?
Round your answer to 2 decimal places.

Physics

Center of mass and momentumTwo masses collide on a frictionless horizontal floor and in a perfectly inelastic collision. Mass 1 is 4 times that of mass 2. Velocity of mass 1 = 12 m/s to the right while the velocity of mass 2 = 18 m/s to the left. What is the velocity and direction of the resulting combined mass? Round your answer to 2 decimal places.

Physics

Center of mass and momentumA 5.0 kg fish moving at 6.6 m/s eats a 1.5 kg fish at rest. Neglecting friction, what is the velocity of the fish after his lunch?

Physics

Center of mass and momentumA 65 g bullet is shot at 400 m/s into a 3 kg block of wood at rest. How much kinetic energy is lost in this collision?

Physics

Center of mass and momentumA ballerina spins initially at 1.5 rev/s when her arms are extended. She then draws in her arms to her body and her moment of inertia becomes 0.88 kg · m², and her angular speed increases to 4.0 rev/s. What was her initial moment of inertia?

Physics

Center of mass and momentumA 0.005 kg coin moving to the right at 0.25 m/s makes an elastic head-on collision with a 0.015 kg coin that is initially at rest. After the collision, the 0.005 kg coin moves to the left at 0.125 m/s. Find the final velocity of the other coin.

Physics

Center of mass and momentum20. A puck with a mass m1 = 50 g moving at 1.0 m/s approaches a stationary puck with a mass m2 = 100 g on a frictionless air table, and they undergo a sudden two-dimensional elastic collision. After the collision, both pucks have identical speeds, but travel in different directions. What is the angle between the original and final paths of puck with mass m₁? 60° 150° 90° 30° 120°

Physics

Center of mass and momentumA baseball of mass 0.152 kg, travelling horizontally at 37.5 m/s
[E], collides with a baseball bat. The collision lasts for 1.15 ms.
Immediately after the collision, the baseball travels horizontally at 49.5 m/s[W].
(a) Determine the initial momentum of the baseball.
(b) What is the average force applied by the bat to the baseball?
(c) Determine the ratio of the magnitude of this force to the
magnitude of the force of gravity on the baseball.

Physics

Center of mass and momentumTwo 1 kg balls move away from each other,
one traveling 2 m/s to the right, the other
1 m/s to the left.
What is the magnitude of the total momen-
tum of the system?
Answer in units of kg. m/s.
Answer in units of \rm kg\cdot m/s
part 2 of 2
Two 1200 kg cars drive east; the first mov-
ing at 35 m/s, the second at 30 m/s.
What is the magnitude of the total momen-
tum of the system?
Answer in units of kg. m/s.

Physics

Center of mass and momentumA soccer ball with a mass of 0.434 kg approaches a player horizontally with a speed of 16.0 m/s. The player kicks the ball with her foot, which causes the ball to move in the opposite direction with a speed of 22.7 m/s.
(a) What magnitude of impulse (in kg m/s) is delivered to the ball by the player?
(b) What is the direction of the impulse delivered to the ball by the player?
Opposite to the ball's initial velocity
Perpendicular to the ball's initial velocity
In the same direction as the ball's initial velocity
The magnitude is zero.
(c) If the player's foot is in contact with the ball for 0.0600 s, what is the magnitude of the average force (in N) exerted on the player's foot by the ball?

Physics

Center of mass and momentumIn principle, when you fire a rifle, the recoil should push you backward. How big a push will it give? Let's find out by doing a calculation in a very artificial situation. Suppose a man standing on frictionless ice fires a rifle horizontally. The mass of the man together with the rifle is 70 kg, and the mass of the bullet is 10 g. For the steps and strategies involved in solving a similar problem, you may view a Video Tutor Solution.
Part A |
If the bullet leaves the muzzle at a speed of 500 m/s, what is the final speed of the man? Express your answer with the appropriate units.

Physics

Center of mass and momentumA 64 kg canoeist stands in the middle of her canoe. The canoe is 3.1 m long, and the end that is closest to land is 2.6 m from the shore. The canoeist now walks toward the shore until she comes to the end of the canoe. Suppose the canoeist is 3.3 m from shore when she reaches the end of her canoe.
What is the canoe's mass?

Physics

Center of mass and momentumYou are holding a shopping basket at the grocery store with two 0.63-kg cartons of cereal at the left end of the basket. The basket is 0.91 m long.
Where should you place a 1.9-kg half gallon of milk, relative to the left end of the basket, so that the center of mass of your groceries is at the center of the basket?