# Motion Along A Straight Line - Chapter No 2

Right Answers have been shown below in red color.

_{i}to x

_{f}. Of the following values of the initial and final coordinates, which results in the displacement with the largest magnitude?

A) x_{i}= 4 m, x_{f}= 6mB) x_{i}= −4 m, x_{f}= −8 mC) x_{i}= −4 m, x_{f}= 2mD) x_{i}= 4 m, x_{f}= −2 mE) x_{i}= −4 m, x_{f}= 4m

_{i}to x

_{f}. Of the following values of the initial and final coordinates, which results in a negative displacement?

A) x_{i}= 4 m, x_{f}= 6mB) x_{i}= −4 m, x_{f}= −8 mC) x_{i}= −4 m, x_{f}= 2mD) x_{i}= −4 m, x_{f}= −2 mE) x_{i}= −4 m, x_{f}= 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 intervalB) the distance covered during the time interval divided by the time intervalC) one-half its speed at the end of the intervalD) its acceleration multiplied by the time intervalE) 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) 2.5B) 2.0C) 1.75D) 1.5E) 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/hB) 45 km/hC) 48 km/hD) 53 km/hE) 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) 0B) 50 km/hrC) 100 km/hrD) 200 km/hrE) 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) 0B) 50 km/hC) 100 km/hD) 200 km/hE) cannot be calculated without knowing the acceleration

8. The coordinate of a particle in meters is given by x(t) = 16t − 3.0t^{3}, where the time t is in seconds. The particle is momentarily at rest at t = ?

A) 0.75 sB) 1.3 sC) 5.3 sD) 7.3 sE) 9.3 s

^{2}, where b is a constant. The expression for the distance traveled by this car from its position at t = 0 is:

A) bt^{3}B) bt^{3}/3C) 4bt^{2}D) 3bt^{2}E) bt^{3}/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/s^{2}B. 4.0 cm/s^{2}C. 5.0 cm/s^{2}D. 6.0 cm/s^{2}E. 6.67 cm/s^{2}

11. The coordinate of an object is given as a function of time by x = 7t − 3t^{2}, 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/sB) −5 m/sC) 11 m/sD) −11 m/sE.)−14.5 m/s

12. The velocity of an object is given as a function of time by v = 4t − 3t^{2}, 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 0B) is −2 m/sC) is 2 m/sD) is −4 m/sE) cannot be calculated unless the initial position is given

^{2}−3t

^{3}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/s^{2}B) 4 m/s^{2}C) −10 m/s^{2}D) 10 m/s^{2}E) −13 m/s^{2}

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)= 3.5−2.7t^{3}

particle 2: x(t)= 3.5+2.7t^{3}

particle 3: x(t)= 3.5+2.7t^{2}

particle 4: x(t)= 3.5−3.4t−2.7t^{2}

Which of these particles have constant acceleration?

A) All fourB) Only 1 and 2C) Only 2 and 3D) Only 3 and 4E) 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)= 3.5−2.7t^{3}

particle 2: x(t)= 3.5+2.7t^{3}

particle 3: x(t)= 3.5+2.7t^{2}

particle 4: x(t)= 3.5−3.4t−2.7t^{2}

Which of these particles is speeding up for t > 0?

A) All fourB) Only 1C) Only 2 and 3D) Only 2, 3, and 4E) 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/s^{2}. Its average velocity as it goes from x = 2 m to x = 8 m is:

A) 1 m/sB) 2 m/sC) 3 m/sD) 5 m/sE) 6 m/s

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

A) A body having velocity east and acceleration eastB) A body having velocity east and acceleration westC) A body having zero velocity and non-zero accelerationD) A body having constant acceleration and variable velocityE) 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, respectivelyB) negative and positive, respectivelyC) negative and negative, respectivelyD) negative and zero, respectivelyE) positive and zero, respectively

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

A) its velocity must be positiveB) its velocity must be negativeC) it must be slowing downD) it must be speeding upE) 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) L^{2}/T, L^{3}/T^{2}B) L/T^{2}, L^{2}/TC) L/T, L/T^{2}D) L^{3}/T, T^{2}/LE) none of these