A truck starts from rest and rolls down a hill with a constant acceleration. It travels a distance of 400 m in 20 s. Find its acceleration. Find the force acting on it if it’s mass is 7 tonnes (Hint: 1 tonne = 1000 kg.)

Asked by Vishal kumar | 2 years ago |  231

##### Solution :-

Given, distance covered by the truck (s) = 400 meters

Time taken to cover the distance (t) = 20 seconds

Initial velocity of the truck (u) = 0 (since it starts from a state of rest)

From the equations of motion, $$s\,=\,ut+\frac{1}{2}at^2$$

$$Therefore,400 = 0(20s) + \frac{1}{2}(a)(400s^2) = 2ms^{-2}$$

The acceleration of the truck is equal to 2ms-2

As per the second law of  motion, force = $$Mass\,\times\,Acceleration$$

Mass of the truck = 7 tonnes = 7000 kg

Force acting on the truck = 7000 kg $$\times$$ 2 m.s-1 = 14000 kg.m.s-2 = 14000 N

Therefore, a force of 14000 N is acting on the truck.

Answered by Shivani Kumari | 2 years ago

### Related Questions

#### A motorcar of mass 1200 kg is moving along a straight line with a uniform velocity of 90 km/h. Its velocity is

A motorcar of mass 1200 kg is moving along a straight line with a uniform velocity of 90 km/h. Its velocity is slowed down to 18 km/h in 4 s by an unbalanced external force. Calculate the acceleration and change in momentum. Also calculate the magnitude of the force required

#### A hammer of mass 500 g, moving at 50 m s-1, strikes a nail. The nail stops the

A hammer of mass 500 g, moving at 50 m s-1, strikes a nail. The nail stops the hammer in a very short time of 0.01 s. What is the force of the nail on the hammer

#### Two persons manage to push a motorcar of mass 1200 kg at a uniform velocity along a level road. The same motor

Two persons manage to push a motorcar of mass 1200 kg at a uniform velocity along a level road. The same motorcar can be pushed by three persons to produce an acceleration of 0.2 m s-2. With what force does each person push the motorcar? (Assume that all persons push the motorcar with the same muscular effort)

#### The following is the distance-time table of an object in motion

The following is the distance-time table of an object in motion:

 Time (seconds) Distance (meters) 0 0 1 1 2 8 3 27 4 84 5 125 6 216 7 343

(a) What conclusion can you draw about the acceleration? Is it constant, increasing, decreasing, or zero?

(b) What do you infer about the forces acting on the object?