Question

A block of mass 200 kg is accelerated uniformly from a velocity of 6 ${ms}^{-1}$​ to 8 ${ms}^{-1}$​ in 5 s. Calculate the initial momentum, final momentum and the magnitude of the force inserted on the block.

• A. 1200 Ns, 1400 Ns, 50 N
• B. 1200 Ns, 1600 Ns, 60 N
• C. 1500 Ns, 1700 Ns, 40 N
• D. 1200 Ns, 1600 Ns, 80 N

Answer 1

The correct option is D

1200 Ns, 1600 Ns, 80 N

Mass of object (m) = 200 kg

Initial velocity (u) = 6 ${ms}^{-1}$​​

Final velocity (v) = 8 ${ms}^{-1}$​​

Time (t) = 6 s

Step 1: Calculate Initial momentum

$P_{initial}$ ​ = m u = 200 $\times$ 6 = 1200 Ns

Step 2: Calculate Final momentum

$P_{final}$​ = m v = 200 $\times$ 8 = 1600 Ns

Step 3: Calculate the rate of change of momentum

Force exerted on the block, F = $\frac{m(v-u)}{t}$ = $\frac{(1600-1200)}{5}$ = 80 N