A car of mass travelling at hits an obstacle and comes to rest.

PHYSICS · Multi-part · CBSE · Physics · Force and Laws of Motion · Force and Laws of Motion

Problem

A car of mass 1000 kg1000\,\text{kg} travelling at 20 m s−120\,\text{m\,s}^{-1} hits an obstacle and comes to rest. (i) Calculate the magnitude of the impulse delivered to the car. (ii) The front portion of an older model is rigid and brings the car to rest in 0.050 s0.050\,\text{s}. Determine the average force exerted on the car in this case. (iii) A modern design allows the front crumple zone and airbags to increase the stopping time to 0.25 s0.25\,\text{s}. Calculate the new average force acting on the car. (iv) Comment, with suitable figures from your answers above, on the effectiveness of the safety features in reducing injuries to the occupants.

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