a particle moves The area under a velocity-time graph represents: a. change in a

Question

a particle moves The area under a velocity-time graph represents: a. change in acceleration b. acceleration c. displacement d. speed e. change in velocity The diagram shows a velocity-time graph for a car moving in a straight line. At point Q the car must be: a. moving with zero acceleration b. traveling downhill c. traveling below ground-level d. reducing speed e. traveling in the reverse direction to that at point P Starting at time t = 0 an object moves along a straight line. Its coordinate in meters is given by x = 75t-t^2 where t is in seconds when it momentarily stops its acceleration is: a. 9.2 times 10^3 m/s^2 b. 0 c.-73 m/s^2 d. -30 m/s^2 e. -9.8 m/s^2 A car, initially at rest, travels 20 m in 4 s along a straight line with constant acceleration. The acceleration of the car is: a. 9.8 m/s^2 b. 2.5 m/s^2 c. 0.4 m/s^2 d. 1.3 m/s^2 e. 4.9 m/s^2

Explanation / Answer

5. area under a velocity -time graph = displacement

Ans(c)

6. acc. = slope of v vs t

and slope is non-zero at Q hence non-zero acceleration.

at P, v is positive and at Q, v is negative hence it is moving in reverse direction.

slope is negative so acceleration is negative but velocity is also negative,

henc speed will increase .

Ans(e)

7. x = 75t - t^3

v = 75 - 3 t^2

it stops hence v = 75 - 3 t^2 = 0

t= sqrt(25) = 5 sec

a = dv/dt = - 6 t = - 30 m/s^2

Ans(d)

8. d = v0 t + a t^2 / 2

20 = 0 + a (4^2) / 2

a = 2.5 m/s^2

Ans(b)

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.