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A motorcar of mass 1200 kg is moving along a straight line wit... - Science
A motorcar of mass 1200 kg is moving along a straight line with a uniform velocity of 90 km/h. Its velocity is slowed down to 18 km/h in 4 s by an unbalanced external force. Calculate the acceleration and change in momentum. Also calculate the magnitude of the force required.
Given:
Mass (m) = 1200 \text{ kg}
Initial velocity (u) = 90 \text{ km/h} = 90 \times \frac{5}{18} = 25 \text{ m/s}
Final velocity (v) = 18 \text{ km/h} = 18 \times \frac{5}{18} = 5 \text{ m/s}
Time (t) = 4 \text{ s}
1. Acceleration (a):a = \frac{v - u}{t}a = \frac{5 - 25}{4}a = \frac{-20}{4}a = -5 \text{ m/s}^2
2. Change in Momentum:
= mv - mu= m(v - u)= 1200 (5 - 25)= 1200 \times (-20)= -24000 \text{ kg m/s}
3. Magnitude of Force (F):F = maF = 1200 \times (-5)F = -6000 \text{ N}