PHYS chpt. 6
A 4 kg ball has a momentum of 12 kg m/s. What is the ball's speed?
3 m/s
Follow through is important in golf because it results in a greater...
Impulse on the ball
Padded dashboards in cars are safer in an accident than nonpadded ones because an occupant hitting the dash has...
Increased time of impact
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...
Long time
A 1-N apple falls to the ground. The apple hits the ground with an impact force of about...
Not enough information to say
It is correct to say that impulse is equal to...
The change in momentum it produces
A 200-lb person pushes on the back of a 100-lb person. Both people are on skateboards and are initially stationary. After the push, the 200-lb person is moving to the right with a speed of 4 m/s. The 100-lb person is ________.
moving to the left with a speed of 8 m/s B/C - The lighter person is half as massive as the heavier person, she must be moving twice as fast for the magnitudes of their momenta to be equal.
A 2.80-kg blob of putty moving at 4.00m/s slams into a 4.60-g blob of putty at rest. Calculate the speed of the two stuck-together blobs of putty immediately after colliding.
v = 3.99 m/s
Judy (mass 36kg ), standing on slippery ice, catches her leaping dog (mass 15 kg) moving horizontally at 2.8m/s...
.82 m/s = v B/C = (15*2.8)/(15+36)
Two billiard balls having the same mass and speed roll toward each other. What is their combined momentum after they meet?
0
How much impulse stops a 44-kg carton sliding at 3.6m/s when it meets a rough surface?
158.4 rounded up to 160 N*s
A 5000-kg freight car moving at 2 m/s runs into a 10,000-kg freight car at rest. They couple upon collision and move away as one body at...
2/3 m/s B/C - m1v1=m1+m2
A car is driving down the highway with an initial speed of 30 m/s. It slams into the back of an identical car (same mass), which was initially going only 10 m/s (in the same direction as the faster car). If the collision is perfectly inelastic, the final speed of the two cars is...
20 m/s B/C - The final momentum must equal the initial momentum, and since the cars have the same mass, the final speed of the two cars must be the average speed of the two cars prior to the collision.
A 1000-kg car moving at 10 m/s brakes to a stop in 5 s. The average braking force is...
2000 N
A sandbag is motionless in outer space. A second sandbag with 3 times the mass moving at 12 m/s collides with it. They stick together and move at a speed of...
4 m/s. 8 m/s. 3 m/s. 6 m/s. *None of these*
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...
5/6 m/s B/C - m1v1=m1+m2
Which of the following has the largest momentum relative to the Earth's surface?
A Mack truck parked in a parking lot A tightrope walker crossing Niagara Falls The Science building on campus A dog running down the street *A pickup truck speeding along a highway*
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...
Doubled
When a cannonball is fired from a cannon, the momentum of the recoiling cannon is momentarily...
Equal and opposite to the momentum of the fired cannonball
The force that accelerates a rocket in outer space is exerted on the rocket by the...
Exhaust gases
A boxer rides with the punch so as to reduce...
Force
What impulse occurs when an average force of 14N is exerted on a cart for 2.6s ?
Impulse = Ft p=34 kg*m/s
Two objects have the same size and shape, but one is much heavier than the other. When they are dropped simultaneously from a tower, they reach the ground at the same time, but the heavier one has a greater...
Momentum
If a monkey floating in outer space throws his hat away, the hat and the monkey will both...
Move away from each other, but at different speeds.
A stationary 100-kg person is initially holding a 50-kg ball while standing on a skateboard. The person throws the ball to the right, and the ball moves (with respect to the ground) with a speed of 12 m/s. The person on the skateboard.
Moves to the left with a speed of 6 m/s B/C - The person is twice as massive as the ball, his speed must be half that of the ball in order for the two momenta to add to zero.
When a big fish swims into an oncoming smaller fish and swallows it, the momentum of the two-fish system...
Remains the same
A rifle recoils while firing a bullet. The speed of the rifle's recoil is small because the...
Rifle has much more mass than the bullet.
A truck rear-ends a car that is initially stationary. The truck weighs ten times more than the car. Which statement is true about the collision?
The force exerted onto the car is ten times greater than the force exerted onto the truck. The magnitude of the acceleration of the car is equal to the magnitude of the acceleration of the truck. *The magnitude of the acceleration of the car is ten times greater than the magnitude of the acceleration of the truck.* B/C - The forces of the two vehicles have the same magnitude, the vehicle with the smaller mass has the higher acceleration.
A Mack truck and a small Volkswagen collide head-on. Which of the following statements is true about the collision?
The force the Volkswagen exerts on the truck is greater than the force the truck exerts on the Volkswagen. The force the Volkswagen exerts on the truck is smaller than the force the truck exerts on the Volkswagen. *The force the Volkswagen exerts on the truck is equal to the force the truck exerts on the Volkswagen.* B/C -According to Newton's third law, the magnitudes of the two forces are equal.
A glass that falls onto a carpeted floor has less chance of breaking than a glass that falls (from the same height) onto a wooden floor. Why?
The glass that falls onto the carpet takes a longer time to stop. B/C -The impulse is the same, but the glass that falls onto the carpet takes a longer time to stop; thus, the force acting on the glass that hits the carpet is lower than the force acting the glass that hits the wooden floor.
Consider two carts, initially at rest. Cart 1 is twice as massive as cart 2. If you push on cart 1 for 3 seconds and then push on cart 2 with the same force for 3 seconds, how do the final momenta of the two carts compare? (Ignore the effect of friction.)
The momenta of the two carts are equal. B/C - The person pushed on both carts with the same force and for the same time duration, both carts received the same impulse. This means that the change in momentum of the two carts is the same. Since both carts started from rest, the final momenta are equal.
Consider two carts, initially at rest. Cart 1 is twice as massive as cart 2. If you push on cart 1 for 3 seconds and then push on cart 2 with the same force for 3 seconds, how do the final speeds of the two carts compare? (Ignore the effect of friction.)
The speed of cart 2 is twice as great as that of cart 1. B/C - The momenta of the carts are the same, the more massive cart must move more slowly.
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...
The target would be safer than the shooter.
When a falling firecracker explodes, the momenta of its pieces...
Vectorally add to equal the initial momentum of the firecracker
When two vehicles collide, momentum is conserved..
Whether the collision is elastic or inelastic
