Given:
m = 0.14 kg
v = 18 m/s
To find:
Kinetic energy= ?
Explanation:
Kinetic energy of the object is possessed when the object is in motion. It is define as the work done required to accelerate a body from rest to motion. Unit of energy is Joule and it is same as unit of work done. Energy is nothing but the capacity to do work.
Solution:
Kinetic energy of the ball is given by,
Kinetic energy =
m = 0.14 kg
v = 18 m/s
Kinetic energy =
Kinetic energy = 226.8 Joule
Answer:
25N
Explanation:
Given parameters:
Power of the motor = 125W
Average speed = 5m/s
Unknown:
Force supplied to the motor = ?
Solution:
Work done is the force applied to move a body through a particular distance;
Work done = Force x distance
Also,
Work done = Power x time
So;
Force x distance = Power x time
since force is the unknown;
Force =
Speed =
Force =
Now solve;
Force = = 25N
Answer:
The cost of using the hair dryer for 15 minutes is
Explanation:
The parameters given in the question are;
The electric current drawn by the the air dryer, I = 11 A
The voltage to which the hair dryer is connected, V = 120 V
The duration of usage of the hair dryer = 15 minutes = 60 minutes /4 = 1 hour/4 = 0.25 hour
The electrical energy costs $0.09/kW·h
The power consumed by the hair dryer = I × V = 11 × 120 = 1320 Watts = 1.32 kW
The energy used by the hair dryer in 15 minutes (0.25 hour) = 1.32 × 0.25 0.33 kW·h
The energy used by the hair dryer in 15 minutes (0.25 hour) = 0.33 kW·h
The energy cost = $0.09/(kW·h)
Therefore;
The cost of using the hair dryer for 15 minutes (0.25 hour) = 0.33 kW·h/($0.09/(kW·h)) = $33/9 = $3 2/3 = $3.6.