Moving About Questions (help!) (1 Viewer)

[gnomeo]

1) A 1.35 tonne loaded car has its speed reduced by braking from 16.0m/s to 6.3m/s. Each of the four brakes applies a force of 1.02kN. Calculate:
a) the work done by each brake to produce this slowing up
b) how far the car will travel while this happens

2)Find the initial velocity of a 0.40 kg projectile if, after it embeds itself in a 3.6kg block, the combined mass moves off at 20m/s.

3)An object, initially at rest, travels a distance 'd' in a total time 't' at a constant acceleration. What is the total time taken for the object to travel '16d' from rest at the same acceleration?

THANK YOU

 

[bujolover]

2) Find the initial velocity of a 0.40 kg projectile if, after it embeds itself in a 3.6kg block, the combined mass moves off at 20m/s.

From m₁u₁ + m₂u₂ = v(m₁ + m₂):

0.4kg*u₁ + 3.6kg*0ms^-1 = 20ms^-1 (0.4kg + 3.6kg)
0.4kg*u₁ = 20ms^-1*4.0kg
= 80kg.ms^-1
∴, u₁ = (80/0.4)ms^-1
∴, u₁ = 200ms^-1

Hope this helps!

Yours truly,
A fellow Yr 11 student who just survived this topic

 

[gnomeo]

Thank you so much!!!