Uark College Physics 1 Test 3

Two wooden posts are the same height but have different diameters, 10cm and 15cm respectively. A 50 kg box is balanced on top of each post separately. Which post will compress more?

the 10cm post

You throw a ball straight up in the air with a velocity v (kinetic energy K) and it reaches a height H. How high will the ball rise if the initial speed is increased by a factor of 5?

25H

Doof and Shmirtz are trying unsuccessfully to move a large rock. Shmirtz pushes for 8 minutes with a force of 900N. Door pushes for 12 minutes with a force of 1200N. Compare the amount of work they each do on the rock.

neither does any work

Two children, G and H (with unknown masses), slide toward each other at a slippery ice-skating rink. What can be said about their momentum after they collide and hold on to each other?

The combined momentum of G and H is conserved.

Which of these is a larger temperature difference?

1° C and 1 K are the same and larger than 1°F

A red ball and a blue ball have the same mass. They are dropped from the same height. The red ball bounces very well, but the blue ball sticks to the floor and doesn't bounce at all. Which statement below is true about their interactions with the floor?

The blue ball has a smaller change of momentum than the red ball

A ball launcher is used in the lab to launch 3 balls at the same speed from the same height. The red ball is launched 30 degrees up, the yellow ball horizontally, and the blue ball is launched 30 degrees down. If there is no air resistance which ball reaches the ground with the smallest speed?

all reach the floor with the same speed.

Water vapor condenses on the outside of a glass of iced tea. The entropy of the condensation is?

less than the entropy of the water vapor

A diver is spinning in the air with her arms and legs tucked close to her torso. When she extends her arms and legs...

moment of inertia increases and angular velocity decreases

An 20N force is applied to two copper wires. The wires are the same diameter, but one is 0.35m long and the other is 0.65m long. Which one stretches more?

the 0.65m wire.

Students A and B do the same amount of work, but B takes twice as long as A. A's power output is

2 times B

two carts on a frictionless track collide and stick together. Which statement about the cart's momenta is true?

Final total momentum is equal to initial total momentum

You want to put a box toward the end of a board with 2 supports beneath it. What must be true for the board to not tip?

net torque and net force are zero

You drop a tennis ball and watch it bounce. What is the sign of the work done by gravity as it falls to the floor and as it moves upward after bouncing on the floor?

Positive on the way down and negative on the way up

A 1kg book and a 4kg book are lifted individually from a table to the same shelf. What can be said about the change of gravitational potential energy for both?

The change for the 4kg book is 4 times the change for the 1 kg book.