Question

Hey guys!! PLEASE HELP!! NO FAKING ANSWERS PLEASE.A car of mass 1,000 kg moving from a velocity of 40km/h collides with a tree and comes to stop in 5s. What will be the force exerted by car on the tree?

Answer 1

Here is the solution :

In general Force is calculated in Newtons,

1 N = 1 kg m/s²,

Now,
we know that,

Force = Rate of change of momentum,

=> F = ∆P/∆t ,

∆ indicates change, ∆P = P(Final) - P(initial)

Momentum (P) = mass (m) x Velocity(v)

Final momentum = m * v(final)

=> 1000*0 (As the body comes to rest, It's velocity becomes 0)

=> P(Final) = 0,

Initial momentum = m * initial velocity

=> P(initial) = 1000 kg * 40 km/hr

1 km/hr = 5/18 m/s,

=> 40km/hr = 40*5/18 m/s

=> P(initial) = 1000*200/18 Kg m/s,

Time or change in time = 5 sec,

=> Force = ( P(final) - P(initial) )/Time

=> Force = (0 - 1000*200/18)/5 kg m/s²

=> Force = -1000*40/18 N

=> Force (F) = -2222.22222 Newtons

Therefore, The Amount of Force applied by tree = -2222.2222 Newtons,

-ve sign indicates opposite direction to the velocity of car,

Hope you understand, Have a great day,
Thanking you, Bunti 360 !.