Phy 200 - Physics 1 MCQs. List all answers that are valid. (4 points ) 1. In which of the following cases does a car have a negative velocity and a positive acceleration? A car that is traveling in the (a) -x direction at a constant 20 m/s (b) -x direction increasing in speed (c) +x direction increasing in speed (d) -x direction decreasing in speed (e) +x direction decreasing in speed 2. At time t=0 an object is traveling to the right along the x axis at a speed of 10.0 m/s with acceleration of -2.0 m/s2. Which statement is true? (a) The object will slow down, eventually coming to complete stop (b) The object cannot have a negative acceleration end be moving to the right (c) The object will continue to move to the right, slowing down but never coming to a complete stop (d) Object will speed up. 3. Which of the following are scalars? (a) Distance (b) Displacement (c) Speed (d) Velocity (e) Time (f) Mass (g) Weight

4. You drop a rock off a bridge. When the rock has fallen 4m, your drop a second rock. As the two rocks continue to fall, what happens to their velocities? (a) Both increase at the same rate (b) The velocity of the first rock increases faster than the velocity of the second. (c) The velocity of the second rock increases faster than the velocity of the first. (d) Both velocities stay constant

Short answers/definition questions (4 points ) 5. Can a car have a northward velocity and southward acceleration? Explain.

6. Explain the difference between distance and displacement.

7. Can an object have zero velocity and nonzero acceleration at the same time? Explain and give examples. Numerical Problems (12 points) 8. A car slows down uniformly from a speed of 30.0 m/s to rest in 7.00 s. (a) Calculate the acceleration of the car (b)How far did the car travel in this time? (c) Explain the significance of the sign (+ or -) of the acceleration you obtained in part (a). 9. A light plane must reach a speed of 45.0 m/s for takeoff. The plane has a constant acceleration of 3.00 m/s. (a) How long a runaway is needed for this plane to take off? (b) What is the time needed for the plane to take off? 10. A stone is thrown vertically up with a speed of 20.0 m/s from ground level. Calculate (a) Calculate the maximum height. (b) Time to go to the maximum height (c) Total travel time (d) Velocity when it hit the ground.

11. A tone is thrown vertically upward with an speed of 25.0 m/s. (a) Find the possible times when the stone is at 10.5 above the ground. (b) You should have two positive time values obtained in part (b). Why do you have two positive times here? (c) Calculate the velocity of the stone at those two times you found in part (a).