Answer:
(a) 
(b) 
Explanation:
The average power is defined as the amount of work done during a time interval:
According to work-energy theorem, the work done is equal to the change in kinetic energy. So, we have:
Recall that the weight is given by:
The car accelerates uniformly from rest (
). Replacing (3) in (2), we have:
(a) Finally, we replace this in (1):
(b)
Answer:
D a thermometer
Explanation: It measures and track Celcius and Feirinheit.
Friction is an example of thermal energy. As the tiny heat particles move, more warmness is made from the friction.
The average speed is calculated by dividing the total distance of a journey by the total time taken to complete the journey. The distance here is 2 kilometers and the time is 20 minutes or 1/3 hours. Expressing the speed in km/hr:
2 / (1/3) = 6 kilometers per hour
or in meters per second:
2000 / (20 * 60) = 1.67 meters per second.
