Physics 1401 Chp 8 MC questions

If a monkey floating in outer space throws his hat away, the hat and the monkey will both a) move away from each other, but at different speeds b) move away from each other at the same speed c) move a short distance and then slow down d) move a short distance and then go faster e) come to a stop after a few minutes

A

Momentum is transferred to the ground when an apple falls on it. The momentum absorbed by the ground is A) negligible compared to the momentum of the apple. B) greater than that of the apple only if the apple bounces. C) greater than that of the apple in all cases. D) none of these

A

Two billiard balls having the same mass and speed roll toward each other. What is their combined momentum after they meet? a) 0 b) half the sum of their original momentums c) twice the sum of their original momentums d) impossible to determine without additional information

A

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 its momentum over a a) long time b) short time c) same either way

A When time is increased, the force will be less

Recoil is noticeable if we throw a heavy ball while standing on roller skates. If instead we go through the motions of throwing the ball but hold onto it, our net recoil will be a) zero b) the same as before c) small, but noticeable

A initial momentum is 0, final will be the same

Padded dashboards in cars are safer in an accident than non-padded ones because passengers hitting the dashboard encounter a) increased time of impact b) decreased time of impact c)decrease impulse d) increased momentum

A the padding gives you extra time

It is correct to say that impulse is equal to: a) momentum b) the change in momentum it produces c) the force multiplied by the distance the force acts d) velocity multiplied by time

B

A 5-kg fish swimming at a speed of 1 m/s swallows an absent minded 1 kg fish at rest. The speed of the larger fish after this lunch is a) 1/2 m/s b) 2/5 m/s c) 5/6 m/s d) 6/5 m/s e) 1 m/s

C

A karate expert executes a swift blow and breaks a cement block with her bare hand. The magnitude to the force experienced bt her hand is a) zero b) less than the force applied to the cement block c) identical to the force applied to the block d) more than the force applied to the block e) impossible to predict

C

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, both move with a combined momentum of a)less than 1 unit b) more than 1 unit c) 1 unit d) not enough information

C

A rifle recoils while firing a bullet. The speed of the rifle's recoil is small because the a) force against the rifle smaller than against the bullet b) momentum is mainly concentrated in the bullet c) rifle has much more mass than the bullet

C

According to the impulse-momentum equation Ft = change in (mv), a person will suffer less injury falling on a wooden floor which "gives" than on a more rigid cement floor. The "F" in the above equation stands for the force exerted on the a) only the person b) only the floor c) either the force on the person or the force on the floor d) the sum of the force on the person and the force on the floor

C

You're driving down the highway and a bug spatters into your windshield. Which undergoes the greater change in momentum during the time of contact? a) the bug b) the car c) both the same

C

Suppose that a tiny gun made of a strong but very light material fires a bullet that is more massive than the gun itself. For such a weapon a) the target would be safer than the shooter b) recoil problems would be lessened c) conservation of energy would not nold d) conservation of momentum would not hold e) both conservation of energy and momentum would not hold

a Because the gun is lighter than the bullet the recoil momentum will be longer

A large metal ball is shot from a cannon with a short barrel. If the same ball were to be shot from cannon with a longer barrel, its muzzle velocity would be a) less b) more c) the same d) impossible to determine without more information

B

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 impact on the player's hand principally because the a) force of impact is reduced b) relative velocity is less c) tie of impact is increased d time of impact is decreased e) none of these

C

A ball is moving at 3 m/s and has a momentum of 48 kg m.s. What is the balls mass? a) 4 kg b) 12 kg c) 16 kg d) 144 kg e) none of these

C momentum= m(v) 48kg=m/3m/s = 16 kg

A bullet is fired from a gun. The speed of the bullet will be about the same as the speed of the recoiling gun a) because momentum is conserved b) because velocity is conserved c) because both velocity and momentum are conserved d) if the mall of the bullet equals the mass of the gun e) none of these

D

A car traveling along the highway needs a certain amount of force exerted on it to stop. More stopping force may be required when the car has a) more mass b) more momentum c) less stopping distance d) all of these e) none of these

D

A rifle of mass 2kg is suspended by the strings. The rifle fires a bullet of mass .01 kg at a speed of 200 m/s. The recoil velocity of the rifle is about a) .001 m/s b) .01 m/s c) .1 m/s d) 1 m/s e) none of these

D

The force that accelerates a rocket in outer space is exerted on the rocket by the a) rockets nose cone b) rockets wings c) atmospheric presure d) exhaust gases e) none of these

D

The force on an apple hitting the ground depends upon a) the speed of the apple just before it hits b) the time of impact on the grounf c) whether to not the apple bounces d) all of these

D Pi= mvi Pf=mvf delta P= MVf-MVi

The conservation of momentum is most closely related to: a) Newtons 1st law b) Newtons 2nd law c) Newtons 3rd law d) Newtons 4th law

c