PHY 201/211 General Physics

PHY 201/211 General Physics Even Sections. 11:00-11:50 lecture Test I

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Answer all problems.

Do not start working until you are told to do so.

Following information may be useful:

formula sheets are also provided at the back of this test.

(Do not write below)

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Problem No.	Score
1
2
3
4
Total

1. (25points)

Circle the right answers. Only one choice is correct. No penalty for wrong guess.
(Note that there are several versions of the test. Your choices may be different for different versions.)

I. A car is traveling at a speed of 90 kilometers per hour. Convert this to m/s.

A. 25 m/s

B. 90,000 m/s

C. 1500 m/s

D. 0.09 m/s

E. 1.5 m/s

II. The displacement x of an object is given as x = Kt² where t is time. What should be the unit of K?

A. ms²

B. ms^-2

C. m²s²

D. ms

E. no unit

III. An object is dropped (from rest). The distance fallen by the object is proportional to:

A. v

B. t

C. t²

E. None of above.

IV. A rock is thrown downward, instead of being released from rest (at the same level). Which of the following statements is not correct?

A. The rock will have a downward initial velocity.

B. The rock with hit the ground with a higher speed.

C. The ball will reach the floor in a shorter time.

D. The acceleration will become larger.

E. The distance traveled by the rock is the same.

V. A ball is thrown upward. It falls back after reaching the highest point. Which statement is not correct?

A. v = 0 m/s at the highest point.

B. Acceleration and velocity have opposite sign when the ball is going up.

C. Velocity changes sign as the ball goes through the highest point.

D. When the ball is falling down, acceleration must be negative in sign.

E. Acceleration and velocity have the same sign when the ball is coming down.

2. Calculate the average speed and average velocity of a complete round trip in which the outgoing 300 km is covered at 120 km/h, followed by a 90 minutes lunch break, and the return 300 km is covered at 60 km/h.

Solution

3. In the one-hundred-meter dash a sprinter accelerates from rest to a top speed with an acceleration of 2.68 m/s² in 3 second. After achieving the top speed, he runs the remainder of the race without speeding up or slowing down.

a. (8 points)

What is the top speed?

Solution

b. (8 points)

What is the distance run by the sprinter when he is accelerating?

Solution

c. (9 points)

It takes how long for the sprinter to finish the race?

Solution

4. A building is 10.0m tall. From the top of the building a stone is dropped from rest. When the stone is halfway down, a second stone is thrown straight from the top of the building. The two stones strike the ground simultaneously?

a. (10 points)

It takes how long for the first stone to fall half of the height of the building?

Solution

b. (5 points)

It takes how long for the first stone to fall to the ground? Also obtain the time allowed for the second stone to fall in order to reach the ground simultaneously with the first stone.