Question

The army has acquired radar that can track an artillery shell in flight and
determine its origin before it hits. The system erects a sensitive electronic plane
over a broad area and can detect any projectile piercing that plane. After tracking
the shell and plotting its path, system’s computer back tracks the trajectory to
the firing location. The enemy has fired a shell at the radar station. The radar
detects the shell at the coordinates (400 m, 75 m) and again at (200 m, 50 m).
Given that the path of a projectile projected near the surface of the earth is a
parabolic, determine (i) the angle of projection of the shell and (ii) the initial
velocity of projection.
b) It is sometimes claimed “speed kills” referring to the fact that the faster you
travel the worst would be results if an accident were to occur. Explain this claim
with reference to Newton’s second law of motion.

Answer 1

b) During an accident, a fast moving car comes to rest in very short time, this means a very large deceleration is needed. Our body can withstand a certain acceleration. Larger accelerations are fatal to our body.

Hence speed kills.

b)