Question

A trolley, while going down an inclined plane, has an acceleration of 2 cm s-2. What will be its velocity 3 s after the start?

NCERT Class IX
Sciences - Main Course Book

Chapter 8. Motion

Answer 1

The "velocity of the trolley" at 3 s is 0.06 m/s .

Given data:

Acceleration, a = 2 cm/s^2 = 0.02 m/s^2

To find:

Velocity after 3 s = ?

Solution:

The trolley is on the inclined plane,

Thereby, the first equation of motion is to be applied to calculate velocity after 3 sec.

Therefore, we have,

t = 3 sec

u = 0  

$a=2 \ \mathrm{cm} / \mathrm{s}^{2}=0.02 \ \mathrm{m} / \mathrm{s}^{2}$

$v=u+a t$

$v=0+(0.02 \times 3)$

$\Rightarrow v=0.06 \ m / s$

Answer 2

Answer:

Explanation:

Given :-

Acceleration of trolley, a = 2 cm/s² = 0.02 m/s²

Initial speed of trolley, u = 0 (As trolley starts from rest)

Time taken by trolley, t = 3 seconds

To Find :-

Final speed, v = ??

Formula to be used :-

1st equation of motion,

i.e, v = u + at

Solution :-

Putting all the values, we get

v = u + at

⇒ v = 0 + 0.02 × 3

⇒ v = 0.02 × 3

⇒ v = 0.06 m/s

Hence, the final velocity of trolley is 0.06 m/s.

Important Term :-

Final speed - Final speed is that speed which is acquired by the body after its start. It is denoted by v. When a body finally comes to rest, its final speed is zero.