# Motion Along A Straight Line - Chapter No 2

Right Answers have been shown below in red color.

1. A particle moves along the x axis from xi to xf . Of the following values of the initial and final coordinates, which results in the displacement with the largest magnitude?
A) xi = 4 m, xf = 6m B) xi = −4 m, xf = −8 m C) xi = −4 m, xf = 2m D) xi = 4 m, xf = −2 m E) xi = −4 m, xf = 4m
2. A particle moves along the x axis from xi to xf . Of the following values of the initial and final coordinates, which results in a negative displacement?
A) xi = 4 m, xf = 6m B) xi = −4 m, xf = −8 m C) xi = −4 m, xf = 2m D) xi = −4 m, xf = −2 m E) xi = −4 m, xf = 4m

3. The average speed of a moving object during a given interval of time is always:

A) the magnitude of its average velocity over the interval
B) the distance covered during the time interval divided by the time interval
C) one-half its speed at the end of the interval
D) its acceleration multiplied by the time interval
E) one-half its acceleration multiplied by the time interval.

4. Two automobiles are 150 kilometers apart and traveling toward each other. One automobile is moving at 60 km/h and the other is moving at 40 km/h mph. In how many hours will they meet?

A) 2.5
B) 2.0
C) 1.75
D) 1.5
E) 1.25

5. A car travels 40 kilometers at an average speed of 80 km/h and then travels 40 kilometers at an average speed of 40 km/h. The average speed of the car for this 80-km trip is:

A) 40 km/h
B) 45 km/h
C) 48 km/h
D) 53 km/h
E) 80 km/h

6. A car starts from Hither, goes 50 km in a straight line to Yon, immediately turns around, and returns to Hither. The time for this round trip is 2 hours. The magnitude of the average velocity of the car for this round trip is:

A) 0
B) 50 km/hr
C) 100 km/hr
D) 200 km/hr
E) cannot be calculated without knowing the acceleration

7. A car starts from Hither, goes 50 km in a straight line to Yon, immediately turns around, and returns to Hither. The time for this round trip is 2 hours. The average speed of the car for
this round trip is:

A) 0
B) 50 km/h
C) 100 km/h
D) 200 km/h
E) cannot be calculated without knowing the acceleration

8. The coordinate of a particle in meters is given by x(t) = 16t − 3.0t3, where the time t is in seconds. The particle is momentarily at rest at t = ?

A) 0.75 s
B) 1.3 s
C) 5.3 s
D) 7.3 s
E) 9.3 s

9. A drag racing car starts from rest at t = 0 and moves along a straight line with velocity given by v = bt2, where b is a constant. The expression for the distance traveled by this car from its position at t = 0 is:
A) bt3 B) bt3/3 C) 4bt2 D) 3bt2 E) bt3/2

10. A ball rolls up a slope. At the end of three seconds its velocity is 20 cm/s; at the end of eight
seconds its velocity is 0. What is the average acceleration from the third to the eighth second?

A. 2.5 cm/s2
B. 4.0 cm/s2
C. 5.0 cm/s2
D. 6.0 cm/s2
E. 6.67 cm/s2

11. The coordinate of an object is given as a function of time by x = 7t − 3t2, where x is in meters and t is in seconds. Its average velocity over the interval from t = 0 to t = 4 s is:

A) 5 m/s
B) −5 m/s
C) 11 m/s
D) −11 m/s
E.)−14.5 m/s

12. The velocity of an object is given as a function of time by v = 4t − 3t2, where v is in m/s and t is in seconds. Its average velocity over the interval from t = 0 to t = 2 s:

A) is 0
B) is −2 m/s
C) is 2 m/s
D) is −4 m/s
E) cannot be calculated unless the initial position is given

13. The coordinate of an object is given as a function of time by x = 4t2 −3t3 where x is in meters and t is in seconds. Its average acceleration over the interval from t = 0 to t = 2 s is:
A) −4 m/s2 B) 4 m/s2 C) −10 m/s2 D) 10 m/s2 E) −13 m/s2

14. Each of four particles move along an x axis. Their coordinates (in meters) as functions of time (in seconds) are given by
particle 1: x(t)= 3.5−2.7t3
particle 2: x(t)= 3.5+2.7t3
particle 3: x(t)= 3.5+2.7t2
particle 4: x(t)= 3.5−3.4t−2.7t2
Which of these particles have constant acceleration?

A) All four
B) Only 1 and 2
C) Only 2 and 3
D) Only 3 and 4
E) None of them

15. Each of four particles move along an x axis. Their coordinates (in meters) as functions of time
(in seconds) are given by
particle 1: x(t)= 3.5−2.7t3
particle 2: x(t)= 3.5+2.7t3
particle 3: x(t)= 3.5+2.7t2
particle 4: x(t)= 3.5−3.4t−2.7t2
Which of these particles is speeding up for t > 0?

A) All four
B) Only 1
C) Only 2 and 3
D) Only 2, 3, and 4
E) None of them

16. An object starts from rest at the origin and moves along the x axis with a constant acceleration of 4 m/s2. Its average velocity as it goes from x = 2 m to x = 8 m is:

A) 1 m/s
B) 2 m/s
C) 3 m/s
D) 5 m/s
E) 6 m/s

17. Of the following situations, which one is impossible?

A) A body having velocity east and acceleration east
B) A body having velocity east and acceleration west
C) A body having zero velocity and non-zero acceleration
D) A body having constant acceleration and variable velocity
E) A body having constant velocity and variable acceleration

18. Throughout a time interval, while the speed of a particle increases as it moves along the x axis, its velocity and acceleration might be:

A) positive and negative, respectively
B) negative and positive, respectively
C) negative and negative, respectively
D) negative and zero, respectively
E) positive and zero, respectively

19. A particle moves on the x axis. When its acceleration is positive and increasing:

A) its velocity must be positive
B) its velocity must be negative
C) it must be slowing down
D) it must be speeding up
E) none of the above must be true

20. The position y of a particle moving along the y axis depends on the time t according to the equation y = at − bt2. The dimensions of the quantities a and b are respectively:

A) L2/T, L3/T2
B) L/T2, L2/T
C) L/T, L/T2
D) L3/T, T2/L
E) none of these