Answer:
I will answer this in English, we can translate it to:
Why if you charge a mate by an amount of time you are not doing work?
This happens because work is defined as the displacement done by a force:
W = d*F
where W is work, d is the distance, and F is the force.
This means that the amount of time that you are charging your mate does not affect the mechanical work, the only time that you are doing work is when you are lifting him.
Answer:
Option 4
Explanation:
During heating actually heat transfer takes place from a body at higher temperature to a body at lower temperature and the heat transfer takes place until both attain the same temperature
Therefore heat transfer depends on the temperature of the systems
Now while comparing the thermal energies of the systems, if both the systems have same mass then the system which is at higher temperature has greater thermal energy when compared to the system which is at lower temperature
So in this case assuming that both the systems have same mass then the energy will leave the system with greater thermal energy and go into the system with less thermal energy as the system with greater thermal energy in this case will be at higher temperature and we are considering this assumption because thermal energy not only depends on temperature but also depends on mass of the system
Answer:
Centre of gravity is a theoretical point in the body where the total weight of the body is thought to be concentrated. In a uniform gravitational field, the centre of gravity is identical to the centre of mass. Yet, the two points do not always coincide.
Answer:
The impulse on the ball delivered by the floor is 2.52 kg-m/s.
Explanation:
Given that,
Mass of the ball, m = 0.22 kg
It is dropped from an initial height of 1.80 m. It rebounds back after colliding with the floor to a final height of 1.50 m. Initial velocity and final velocity can be calculated using conservation of energy as :
Final velocity,
As the ball rebounds, v = -5.47 m/s
We need to find the impulse on the ball delivered by the floor. We know that impulse is equal to the change in momentum as follows :
So, the impulse on the ball delivered by the floor is 2.52 kg-m/s.
Answer:
34 m/s
Explanation:
The law of conservation of linear momentum dictates that the sum of initial and final momentum should be equal. Momentum is a product of mass and velocity.
Since the canon recoils, its recoil velocity is opposite hence
MV=nu where M and n are mass of cannon and cannoball respectively, v and u are the velocities of cannon and cannon balls respectively.
Substituting 200 kg for M and 1.7 m/s for v then 10 kg for n
200*1.7=10u
U=200*1.7/10=34 m/s
