Answer:
(i) the resistive force exerted by the sand on the bullet is - 1 x 10⁵ N
(ii) the time taken by the bullet to come to rest is 1 x 10⁻⁴ s
Explanation:
Given;
mass of bullet, m = 10 g = 0.01 kg
speed of the bullet, v = 10³ m/s
distance traveled by the bullet, d = 5 cm = 0.05 m
(i) the resistive force exerted by the sand on the bullet
the acceleration of the bullet is given by;
v² = u² + 2as
0 = (10³)² + a(2 x 0.05)
-0.1a = (10⁶)
-a = (10⁶) / 0.1
a = -1 x 10⁷ m/s²
The resistive force is given by;
F = ma
F = (0.01)(-1 x 10⁷)
F = - 1 x 10⁵ N
(ii) the time taken by the bullet to come to rest.
v = u + at
0 = 10³ + (-1 x 10⁷ t)
1 x 10⁷ t = 10³
t = 10³ / 10⁷
t = 1 x 10⁻⁴ s
