Question

A 6000 kg lorry is reversing into a parking space at a speed of 0.5 m/s but collides with a car. The crumple zone of the car stops the lorry in 1.5 seconds. What was the impact force?

Answer 1

Answer:

-200 N

Explanation:

Force: This can be defined as the product of mass and acceleration The S.I unit is N

The expression for force is given as

F = m(v-u)/t................... Equation 1

Where F = Impact force, m = mass of the lorry , v = Final velocity of the lorry , u = initial velocity of the lorry, t = time

Given: m = 6000 kg, v = 0 m/s (the lorry was stopped), u = 0.5 m/s, t = 1.5 s

Substitute into equation 1

F = 6000(0-0.5)/1.5

F = -300/1.5

F = -200 N.

Note: The negative sign shows that the impact force act in opposite direction to the initial motion of the lorry

Answer 2

Answer:

Impact force is 3000Nsec

Explanation:

The impact force is called Impulse.

impulse is the product of the average force acting on a article and the time during which it acts;

Impulse(I)=Force x Time

Time= 1.5seconds

Force= Mass x velocity/time

Force=6000 x 0.5/1.5

Force=2000N

therefore;

Impulse(I)=2000 x 1.5

I=3000Nsec