Chapter 6 Physics Homework

The total momentum of a flock of identical birds could be zero only if the birds are

flying in different directions

A slowly moving ship can have a greater momentum than a fast moving racing car when

its mass times velocity is greater than that of the car

How much impulse stops a 60-kg carton sliding at 5 m/s when it meets a rough surface

Impulse = change in momentum J = 60 kg x 5 m/s = 300 N*s

What impulse occurs when an average force of 15 N is exerted on a cart for 2.2 s

Impulse = force x time = 15 N x 2.2 s = 33 kg* m/s

What is the momentum of a 9-kg bowling ball rolling at 2.6 m/s

Momentum = mass x velocity = 9 (2.6) = 23 kg*m/s

Cassy can get more force on the bricks she breaks with the blow of her bare hand when

her hand is made to bounce from the bricks

Follow through is important in golf because it results in a greater

impulse on the ball

A 5.2-kg fish swimming 0.90 m/s swallows an absentminded 1.0-kg fish swimming toward it at a speed that brings both fish to a halt immediately after lunch. Find the speed of the approaching smaller fish before lunch.

initial momentum = final momentum (zero) v2= v1(m1/m2) = .9(5.2/1.0) = 4.7 m/s

A same-size iron ball and wooden ball are dropped simultaneously from a tower and reach the ground at the same time. The iron ball has a greater

momentum

The quantity that is called impulse can be measured by the

product of force and time

When a big fish swims into an oncoming smaller fish and swallows it, the momentum of the two-fish system

remains the same

The speed of a 4 kg ball with the momentum of 12 kg*m/s is

speed = momentum/mass = 12/4 = 3 m/s

A freight train rolls along a track with considerable momentum. If it rolls at the same speed but has twice as much mass, its momentum is

twice

In which is momentum conserved: an elastic collision or an inelastic collision

Momentum is conserved in both

An ostrich egg of mass m is tossed at a speed v into a sagging bed sheet and is brought to rest in a time t. Part A: Find the force acting on the egg when it hits the sheet Part B: If the mass of the egg is 0.90 kg , its initial speed is 1.7 m/s , and the time to stop is 0.20 s, find the average force on the egg.

Part A: Force = mass x velocity / time Part B: (.9 x 1.7) / .2 = 7.7 N

When two vehicles collide, momentum is conserved

whether the collision is elastic or inelastic