Explanation : Tina is doing work all of the time because whiles she’s pulling and allowing the rope to be pulled her body using muscles to keep herself upright and a firm grip on the rope.
A) 350 J
- The initial internal energy of the cup is
- The final internal energy of the cup is

According to the first law of thermodynamics:

where
Q is the heat absorbed by the system
W is the work done on the system
The work done on the system in this case is 0, so we can rewrite the equation as

And so we find the heat transferred

B) IN the cup
Explanation:
in this situation, we see that the internal energy of the cup increases. The internal energy of an object/substance is proportional to its temperature, so it is a measure of the average kinetic energy of the molecules of the object/substance. Therefore, in this case, the temperature (and the energy of the molecules of the substance) has increased: this means that heat has been transferred INTO the system from the environment (the heat came from the sun).
Answer:
(θ) = 60°
Explanation:
Given:
Speed of canoe Vc = 2 m/s
Speed of River Vr = 1 m/s
Computation:
Vc (Cosθ) = Vr
2 (Cosθ) = 1
(Cosθ) = 1 / 2
(Cosθ) = (Cos60)
(θ) = 60°
Answer:
Kinetic energy is maximum when the player hits the ball.
Explanation:
Kinetic energy
, where m is the mass and v is the velocity.
So kinetic energy is proportional to square of velocity.
Velocity is maximum when the player hits the ball.
So kinetic energy is maximum when the player hits the ball.
An electron is negatively charged.