Answer:
Force on superball will be 
Explanation:
We have given mass of superball m = 52 gram = 0.052 kg
Velocity change from 20 m/sec downward to 14 m/sec upward
Let downward velocity is positive then upward velocity is negative
So downward velocity is + 20 m/sec and upward velocity is -14 m/sec
Time is given as 1800 sec
We know that acceleration is rate of change of velocity
So 
According to newton second law
Force = ma = 0.052×0.0188
Answer:
Efficiency = 90 %
Wasted energy = 10 %
Explanation:
Since we have the input energy and useful output energy of the electric kettle, the only thing we are required to calculate here is its efficiency. This is gotten from
E = useful output energy/input energy × 100
E = 9/10 × 100 = 90 %
The percentage of wasted energy is
W = wasted energy/input energy × 100
W = 1/10 × 100
W = 10 %
Answer:
just awnsered this one your awnser is the the second option
First question: 800J
Second question: 20.4m
