Physics Test 3 Flashcards
(31 cards)
Which slide would give the girl the greatest speed at the bottom?
A. Steep 2 bumps B. Steep 1 bump C. Steep straight D. Steep hump E. she would have the same speed at the bottom of each
E. she would have the same speed at the bottom of each
An acorn falls from a tree. Compare its kinetic energy K, to its potential energy U. A. K increases and U decreases B. K decreases and U decreases C. K increases and U increases D. K decreases and U increases
A. K increases and U decreases
A mass is attached to one end of a string. The other end is attached to a rigid support. The mass is released at A and swings in a vertical arc to points B, C, and D. Neglect air resistant and use g=10 m/s^2. At what point does the mass have the most potential energy? A. A highest point B. B second highest point C. C third highest point D. D lowest point
A. A highest point
At what point does the mass have the most kinetic energy? A. Highest point B. Second highest point C. Third highest point (straight down) D. Lowest point
C. Third highest point (straight down)
At what point does the mass have its highest speed? A. Highest point B. Second highest point C. Straight down D. Lowest point
C. Straight down
Swimmers at a water park can enter a pool using one of two frictionless slides of equal height. Slide 1 approaches the water with uniform slope; slide 2 dips rapidly first, then levels out. Is the speed at the bottom of slide 2 greater than, less than, or the same speed at the bottom of the slide?
The same
Is it possible for the gravitational potential energy of an object to be negative?
A. Yes
B. No
A. Yes
You and your friend both solve a problem involving a skier going down a slope, starting from rest. The two of you have chosen different levels for y=0 in this problem. Which of the following quantities will you and your friend agree on?
A. Skier’s change in PE
B. Skier’s final KE
C. Skier’s PE, skier’s change in PE, skier’s final KE
D. Skier’s PE and skier’s final KE
E. skier’s change in PE and skier’s final KE
E. skier’s change in PE and skier’s final KE
Two paths lead to the top of a big hill. One is steep and direct, while the other is twice as long but less steep. How much more potential energy would you gain if you take the longer path? A. The same B. Twice as much C. Four times as much D. Half as much E. you gain no PE in either case
A. The same
How does the work required to stretch a spring 2 cm compare with the work required to stretch it 1 cm? A. Same amount of work B. Twice the work C. Four time the work D. Eight times the work
C. Four times the work
A mass attached to a vertical spring causes the spring to stretch and the mass to move downwards. What can you say about the spring’s potential energy and the gravitational potential energy of the mass?
A. Both spring PE and gravitational PE decrease
B. Spring PE increases and gravitational PE decreases
C. Both spring PE and gravitational PE increases
D. Spring PE decreases and gravitational PE increases
E. spring PE increases and gravitational PE is constant
B. Spring PE increases and gravitational PE decreases
Three balls of qualifying mass start from rest and roll down different ramps. All ramps have the same height. Which ball has the greater speed at the bottom of its ramp? A. Steep and short B. Steep and medium long C. Steep and longest D. Same speed for all balls
D. Same speed for all balls
Paul and Kathleen start from rest at the same time on frictionless water slides with different shapes. At the bottom, whose velocity is greater?
A. Paul
B. Kathleen
C. Both the same
C. Both the same
You see a leaf falling to the ground with constant speed. When you first notice it, the leaf has initial total energy PEi+KEi. You watch the lead until just before it hits the ground, at which point it has final total energy PEf+KEf. How do these energies compare?
A. PEi+KEi > PEf+ KEf
B. PEi+ KEi = PEf + KEf
C. PEi + KEi < PEf + KEf
A. PEi + KEi > PEf + KEf
What is an inelastic collision?
Momentum is conserved but kinetic energy is not conserved
What is a elastic collision?
Both momentum and kinetic energy are conserved
A system of particles is known to have a total kinetic energy of zero. What can you say about the total momentum of the system?
A. Momentum of the system is positive
B. Momentum of the system is negative
C. Momentum of the system is zero
Momentum of the system is zero
A net force of 200 N acts on a 100 kg boulder, and a force of the same magnitude acts on a 130 g pebble. How does the rate of change of this boulder’s momentum compare to the rate of change of the pebble’s momentum?
A. Greater than
B. Less than
C. Equal to
C. Equal to
A net force of 200 N acts on a 100 kg boulder, and a force of the same magnitude acts on a 130 g pebble. How does the rate of change of this boulder’s velocity compare to the rate of change of the pebble’s velocity?
A. Greater than
B. Less than
C. Equal to
B. Less than
A ball tied to a string is being whirled around in a circle. What can you say about the work done by tension?
A. Tension does no work at all
B. Tension does negative work
C. Tension does positive work
A. Tension does no work at all
In the SI systems of units, power has the same units as A. Js/m B. Jm/s C. Nm/s D. W/m E. W/s
C. Nm/s
You want to load a box into the back of a truck. One way is to lift it straight up through a height h, as shown, doing a work W1. Alternatively, you can slide the box up a loading ramp a distance L, doing a work W2. Assuming the box slides on the ramp without friction, which of the following is correct
A. W1W2
B. W1=W2
If an object has momentum, then it must also have A. Potential energy B. Kinetic energy C. Acceleration D. Force
B. Kinetic energy
A simple pendulum, consisting of a mass m and a string of length L, swings upward, making an angle theta with the vertical. The work done by the tension force is A. Zero B. mgL C. mgLcostheta D. mgLsintgeta E. mgLtantheta
A. Zero
