Answer:
The force exerted by the floor is 80 N.
Explanation:
Given that,
Mass of ball = 0.5 kg
Velocity= 4 m/s
Time t = 0.05 s
When the ball rebounds then the kinetic energy is

Where, m = mass of ball
v = velocity of ball
Put the value into the formula


The average force exerted by the floor on the ball = change in kinetic energy over collision time


Hence, The force exerted by the floor is 80 N.
<span>The answer to this problem is magnesium. I hoped I helped someone with this</span>
Answer:
the minimum value of torque is 101.7 N-m.
Explanation:
Given that,
Mass of bundle of shingles, m = 30 kg
Upward acceleration of the shingles,
The radius of the motor of the pulley, r = 0.3 m
Let T is the tension acting on the shingles when it is lifted up. It can be calculated as :
T-mg=ma
T=m(g+a)

Let
is the minimum torque that the motor must be able to provide. It is given by :

the minimum value of torque is 
Answer: depth= 1875m
Explanation: divide t by 2 because its echo it will go and come back thats why we divide it with 2
Then apply formula Depth(d)=velocity (v)/time (t)
Putting values we get ,
d=1500/0.4
d=1875m