Answer:
Explanation:
Given

Motor reverse its direction when \omega =0



(b)





Answer:
Explanation:
mass of elephant, m1 = 5240 kg
mass of ball, m2 = 0.150 kg
initial velocity of elephant, u1 = - 4.55 m/s
initial velocity of ball, u2 = 7.81 m/s
Let the final velocity of ball is v2.
Use the formula of collision


v2 = - 16.9 m/s
The negative sign shows that the ball bounces back towards you.
(b) It is clear that the velocity of ball increases and hence the kinetic energy of the ball increases. This gain in energy is due to the energy from elephant.
Formula for Electric Field strength , E = V/d
where V = Voltage in volts, and d = distance of separation in meters.
d = 0.5 cm = 0.005 m, V = 12 V
E = V/d = 12 / 0.005
E = 2400
Electric Field Strength = 2400 Volts/meter
Answer:We have , a relation in frequency f and wavelength λ of a wave having the velocity v as ,
v=fλ ,
given f=60Hz , λ=20m ,
therefore velocity of wave , v=60×20=1200m/s