physics 9

The impulse necessary to cause a change of momentum at 20 kg-m/sec for a 5 kg object is?

20 N sec

A 4 kg ball has a momentum of 12 kg-m/sec. What is its speed?

3 m/s.

Which has the greatest momentum: A tractor with a mass of 2,350 kg moving at a velocity of 26 m/sec A boat with a mass of 1,310 kg moving at a velocity of 53 m/sec A truck with a mass of 6,220 kg moving at a velocity of 11 m/sec A car with a mass of 1,440 kg moving at a velocity of 39 m/sec

boat with a mass of 1310 kg

A skateboarder increases her speed from 2 m/sec to 4 m/sec. Her momentum does what?

increases

When you are in the way of a fast moving object and can't get out of its way, you will suffer a smaller force of impact if you decrease momentum over ?

- a long time.

A mass with a momentum of 40 kg-m/sec receives an impulse of 30 n-sec in the direction opposite to its motion, its final momentum is?

-10kg m/sec.

A 2 kg piece of clay moving at 3 m/sec strikes and sticks to a second 2 kg piece of clay moving at 1 m/sec in the opposite direction. Calculate the speed of the combined piece of clay?

-2 m/sec

The time required to stop a 200 kg wagon moving at 5 m/sec with a 40 newton force is?

-25 seconds.

What is the momentum of a 30 kg cart moving at a speed of 10m/sec?

-300 kg m/sec

A billiard ball collides with a second ball and stops. The total momentum of the billiard balls?

-Remains the same.

Air bags help reduce injury in accidents by?

-Stopping the force from driving. Increasing time.

An astronaut, floating alone in outer space, throws a baseball. If the ball floats away at a speed of 20 m/sec, the astronaut will?

-The astronaut will move in the opposite direction at a lower speed.

To increase the final momentum of a golf ball, a golfer should?

-increase the time of contact with the ball.

Compared to falling on a stone floor, a wine glass may not break when it falls on a carpeted floor because?

-stopping time is longer for the carpet.

A piece of putty moving with 1 unit of momentum strikes and sticks to a heavy bowling ball that is initially at rest. After the putty sticks to the ball, they both move with a combined momentum of?

1 unit

A 100 kg car moving at 10 m/sec brakes to a stop in 5 seconds. What is the average braking force?

2000N

The unit used to measure momentum is?

Kg m/sec

A car traveling along the highway needs a certain amount of force exerted on it to stop it in a certain distance. When is more stopping force required?

More mass and momentum and less stopping distance.

A 5000 kg freight car runs into a 10,000 kg freight car at rest. They couple upon collision and move with a speed of 2 m/sec. What was the initial speed of the 5000 kg

-6 m/s.

During a football game, a 90 kg running back moving east is tackled by a 110 kg defensive back running west at 5 m/sec. Both players, together, move east at 1.5 m/sec after the tackle is made. Before he is tackled, at what speed is the running back moving?

-9.4 m/s

It is correct to say that impulse is equal to what?

-Change in momentum.

heavy truck and a small car rolling down a hill at the same speed are forced to stop in the same amount of time. Compared to the force that stops the car, the force needed to stop the truck is?

-Greater force is needed.

A n egg dropped on thesidewalk normally breaks, but an egg dropped on the grass might not break because?

-the grass is softer and the time interval for stopping is greater.

You are driving down the highway and a bug slams into your windshield.Which undergoes the greater change in momentum during the time of contact?

-the momentum is the same.

In order to catch a ball, a baseball player extends the hand forward before impact with the ball and then lets it ride backward in the direction of the ball's motion. Doing this reduces the force of the impact on the player's hand principally because the?

-the time of impact is increased.

You throw a basketball forward while standing on a skateboard. This causes?

Motion going backwards of the board and you.

When you jump from an elevated position you usually bend your knees upon reaching the ground. Why do you do this?

The impact is great for a stiff-legged landing. 1/10

When comparing the momentum of 2 moving objects, which object has the greater momentum? The one with greater mass, velocity, both, neither?

The object with greater mass and velocity.

Two objects have the same size and shape, but one is much heavier than the other. When dropped at the same time, which has the greater momentum?

The one that is heavier.

Metal sphere A has a mass of 5 kilograms, and metal sphere B has a mass of 9 kilograms. The spheres are dropped from a fourth-story window at the same time. As they reach the ground, who has the larger momentum?

metal B