Question

A force acts on a trolley of mass 50 kg for 8 s. It moves through a distance of 30 m in the next 3 s. Calculate the :
(a) velocity attained
(b) acceleration produced, and
(c) magnitude of force applied

Answer 1

As we know :

V =
$\frac{s}{t}$

V =
$\frac{30}{3}$

V = 10m/s

b)Now,
 v = u + at

=> 10 = 0 + a × 8

=> 10 = 8a

=> a = 10/8 = 1.25 m/s^2

c)

F = ma

F= 50×1.25

F = 62.5 N

What is force ?

=> A pull or push on an object is called force. It can start ,stop a body or change its direction of motion.

"N" (Newton) is the SI unit of Force .

In CGS it's Unit is Dyne .

1 Newton =
${10}^{5} dyne$

Velocity :

It is a vector quantity and it is defined as the ratio of displacement to the total time. Velocity maybe zero or positive or negative.

Velocity =
$\frac{displacement}{time}$
Acceleration :

It is defined as the rate of change of velocity.

Acceleration =

$\frac{final \: velocity - initial \: velocity}{time}$
#Be Brainly !!

Answer 2

Let's understand the question first.

A force acts on a trolley of mass 50 kg for 8s.
So Mass of trolley is 50kg. initially it was at rest. Then an unknown force(let's say F) acts on it for 8 seconds. This force will increase in velocity from 0 to some v in 8 seconds.

It moves through a distance of 30 m in the next 3 s.
So force is removed at 8th second. Now the trolley has attained velocity v and moves at constant velocity v. Within 3 second, it moved 30m.

So from t=0 to t=8 sec, the trolley was in an accelerated motion.

from t=8s to t=11s, it was moving at constant velocity v.

Coming to the questions:

a.

We need to find the velocity attained.

I have explained the velocity attained is v.

It had moved 30m in 3s at constant velocity v.

we know displacement = v × t

=> 30 = v × 3

=> v = 30/3

=> v = 10 m/s

(b)

We need to find the acceleration produced

acceleration was produced in the first 8 second of the motion when force was acting.

During these 8 sec, velocity changed from 0 to v(=10 m/s)

Use v = u + at

=> 10 = 0 + a × 8

=> 10 = 8a

=> a = 10/8 = 1.25 m/s^2

acceleration produced is 1.25 m/s^2.

(c)

We need to find the magnitude of force applied

This is straight forward. We know F = ma

=> F = 50 × 1.25

=> F = 62.5 N

Hence, magnitude of force applied is 62.5 N

Any doubt, ask in comment.