The distance you free-fall from rest is D = (1/2) (g) (T²) <== memorize this
Height of the platform = (1/2) (9.8 m/s²) (2.4 sec)²
Height = (4.9 m/s²) (5.76 s²)
Height = (4.9/5.76) meters
Height = 28.2 meters (a VERY high platform ... about 93 ft off the water !)
Without air-resistance, your horizontal speed doesn't change. It's constant. Traveling 3.1 m/s for 2.4 sec, you cover (3.1 m/s x 2/4 s) = 7.4 m horizontally.
0.4 N-s is the "impulse" acted on the "beach ball".
Option: C
Explanation:
Given that,
Mass of the "beach ball" is 0.1 kg.
The speed of the ball hits is 4 m/s.
We know that,
Whenever an object is collide with other object then an impulse is acted on object, this "impulse" causes "change in momentum".
Impulse acted on the beach ball is "mass" times "velocity".
Impulse = mass × velocity
Impulse = 0.1 × 4
Impulse = 0.4 kg m/s
Impulse = 0.4 N-s
Therefore, the "impulse" acted on the ball is 0.4 N-s.
mass of the box = 20 kg
force of friction on the box due to surface
similarly kinetic friction on it
now the weight of the suspended block will be
so here the weight of the suspended block is less than the limiting friction on it
So here we will say that friction will counter balance the weight of the suspended block and it will not move at all
So acceleration of the box will be zero
