Question

Car A mass 1.5 ton travelling 90kmph collides with another car of mass 1000kg travelling at same direction. After collision the velocity of car A becomes 20m/s . Calculate the velocity of car B after collision

Answer 1

Answer:

F=ma

Let’s collect the givens (and identify the unknown as “F” for force):

Distance is 50 m

Mass (m) is 1,000 Kg (i.e., a metric ton)

Initial velocity vi is 20 m/s

Final velocity vi is zero

The deceleration is a velocity change of -20 m/s (which over a distance of 50 m), but we don’t know the time (t) over which it occurs.

Assuming the acceleration (or negative deceleration) was constant, the average velocity was 10 m/s, so the time to travel 50m was 5 seconds Therefore the acceleration was:

−20ms÷5s

−4ms2

Therefore, given F=ma or

F=1000Kg∗(−4)m/s/s,

the retarding force is -4000 N (since 1 N is defined as 1 Kg m /s^2)