Question

The mass of my car is 1000kg. If it broke down I could push it with a force of 500N. How long would it take me to push it 100m to the petrol station?

Answer 1

Answer:

Time = 10 s

Explanation:

Given:

• Mass of the car = 1000 kg
• Force applied = 500 N
• Distance = 100 m
• Initial velocity = 0 m/s

To Find:

• Time taken

Concept:

First find the acceleration of the car. Substituting the values in the second equation of motion gives us the value of time.

Solution:

First we have to find the acceleration of the car.

By Newton's second law of motion we know that,

F = m × a

where F = force applied

           m = mass of the car

           a = acceleration

Substituting the data,

1000 = 500 × a

a = 1000/500

a = 2 m/s²

Hence acceleration of the car is 2 m/s².

Now we have to find the time taken.

By the second law of motion we know that,

s = ut + 1/2 × a × t²

where s = distance

           u = intial velocity

           t = time taken

           a = acceleration

Substitute the data,

100 = 0 × t + 1/2 × 2 × t²

t² = 100

t = √100

t = 10 s

Hence the time taken would be 10 s.