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:
196J
Explanation:
Given parameters:
Mass of skateboard = 1kg
Height off the ground = 20m
Unknown:
Potential energy = ?
Solution:
The potential energy is the energy due to the position of a body above the ground.
It is mathematically expressed as:
Potential energy = mass x acceleration due gravity x height
Potential energy = 1 x 9.8 x 20 = 196J
Answer:
Specific heat
Explanation:
The specific heat is the amount of heat, that is energy in transfer to or from a thermodynamic system, required to raise the temperature of 1 g of substance by one degree Celsius or one Kelvin, since one degree on the Celsius scale is equal to one Kelvin.
Answer:
option (c)
Explanation:
According to the newton's third law, for every action there is an equal and opposite reaction.
As the astronaut throw the tool away from the shuttle, it means the action force is in the direction away from the shuttle and according to Newton's third law, the reaction force is getting in the direction of shuttle.
Answer:
Explanation:
Angular momentum is calculated as:
L = I * ω
The inertia of the disc is:
So, the angular momentum is:
