Introduction to Kinematics Practice

Name: ______

Introduction to Kinematics Practice

1. A particle moves along a straight line, x. At time t = 0, its position is at x = 0. The velocity, v, of the object changes as a function of time, t, as indicated on the graph below.

A. What is x at t = 1 s?

B. What is the acceleration at t = 2 s?

C. What is x at t = 3 s?

D. What is the average velocity between t = 0 and t = 3 s?

E. What is the average speed between t = 0 and t = 3 s?

F. Make a plot of x vs. t between t = 0 and t = 3 s. Indicate clearly at t = 0, 1, 2 and 3 s what exactly the x positions are.

2. At t = 0 s, a stone is thrown straight up from ground level with a speed of 20 m/s. Ignore air drag and assume g = 10 m/s2.

A. At what time will this stone reach its highest point and how high will it then be above the ground?

B. A second stone is thrown straight up from ground level 2 seconds after the first. How many meters above the ground is the first stone at that moment?

C. At what speed should the second stone be thrown if it is to hit the first stone 1 second after the second stone is thrown?

3. Given: x = t3 – 2.0t2 + 4.0t – 6.0 meters,

A. Find xo and vo (at t = 0).

B. Find x, v and a at t = 4.0 s.

4.

Average Velocity and Acceleration

List the interval(s) in which:

A. v = 0 B. v > 0 C. v < 0

D. a = 0 E. a > 0 F. a < 0

Instantaneous Velocity and Acceleration

List the time(s) when:

A. v = 0

B. v goes from zero to positive

C. v goes from positive to negative

D. a goes from negative to positive

E. a goes from zero to negative

5. A bullet shot horizontally from a gun. At the same instant, another bullet is simply dropped from the same height. Neglecting air resistance, the bullet shot from the gun

A. strikes the ground much later than the dropped bullet.

B. never strikes the ground.

C. strikes the ground at approximately the same time as the dropped bullet

D. travels in a straight line.

E. strikes the ground much sooner than the dropped bullet.

6. A girl on the edge of a vertical cliff 45 m high throws a stone horizontally outwards with a speed of 20 m/s. It strikes the ground at what horizontal distance from the foot of the cliff?

A. 10 m B. 20 m C. 40 m D. 60 m E. 80 m

7. The brakes on your car can slow you at a rate of 5.2 m/s2. If you are going 137 km/h (38.1 m/s) and suddenly see a state trooper, what is the minimum time in which you can get your car under the 90 km/h (25.0 m/s) speed limit? (The answer reveals the futility of braking to keep your high speed from being detected with a radar or laser gun.)

8. The graph depicts the motion of a particle moving along an x axis with a constant acceleration. The figure's vertical scaling is set by xs = 6.0 m. What are the particles initial velocity, acceleration and the direction of the particle's acceleration?

9. A moving car accelerates at 3.0 m/s2 for 5.0 seconds to reach 25 m/s. What was the initial speed?

A. 0 m/s B. 5.0 m/s C. 10 m/s D. 15 m/s E. 20 m/s

10. A car goes from 0.0 to 10.0 m/s over a distance of 10.0 m. What is its acceleration?

A. 5 m/s2 B. 4 m/s2 C. 1 m/s2 D. 2 m/s2 E. 10 m/s2

Solutions:

1. A. +3 m B. -3 m/s2 C. +3 m D. +1 m/s E. 2 m/s

2. A. 2s, 20 m B. 20 m C. 20 m/s

3. A. -6.0 m, 4.0 m/s B. 42 m, 36 m/s, 20 m/s2

4. AVG: A. 0-1 s B. 1-3 s C. 3-5 s, 5-7 s D. 0-2 s, 5-7 s E. 4-5 s F. 2-4 s

INST: A. 0-1 s, 3 s, 5 s B. 1 s C. 3 s D. 4 s E. 2 s

5. C 6. D 7. 2.5 s 8. 0 m/s, 4.0 m/s2, + direction 9. C 10. A