Answer:
Explanation:
Given
mass m collides elastically with floor and jump to its original height I .e.velocity of rebound is same as the initial velocity
Impulse imparted by steel ball to the ground is given by the change in momentum of steel ball

and impulse is product of average force and time
so we need time to calculate the average force. So, option e is correct
Answer: The minimum time between pulses (in fresh water)
= 0.3106 s
Explanation:
To calculate the speed of echoes sounds, we will use
Speed = 2x/t
Where x = distance and t = total time.
Please note that:
sound travels at 343 m/s in air. But it travels at 1,481 m/s in water (almost 4.3 times as fast as in air);
Total distance = 2 × 230 = 460m
Using speed of sound in water
1481 = 460/t
t = 460/1481
t = 0.3106
Answer:

Explanation:
The frequency of a light is inversely proportional to its wavelength. It is given by:

The speed of the red light, v = 3.0 × 10⁸ m/s
The wavelength of the red light, λ = 690 nm = 690 ×10⁻⁹ m

Thus, the frequency of red light emitted by neon sign having wavelength 690 nm is 
The correct answer is the family van. Joseph is sitting inside of it and it doesn't move relative to him. The van is moving and everything outside the van is moving relative to Joseph so the library, Maria and <span>Jane's house are moving relative to him.</span>