First, we need to convert the pressure in SI units. Keeping in mind that
:
The initial and final volume of the gas are (keeping in mind that
):
So, the work done on the gas by the surrounding is
And the final positive sign means that this work corresponds to an increase in internal energy of the gas.
Answer:
c)wind
Explanation:
Wind from the given choices will have the greatest amount of kinetic energy.
Kinetic energy is the energy due to motion of a body. It is different from the energy at rest in a body.
- Wind is air in motion.
- Wind energy is a form of kinetic energy in motion.
A book on a table, a slice of pizza and a person at the top of the stairs are all at rest and will possess potential energy.
Answer : The correct option is, (D) A machine does 400 joules of work in 5 seconds.
Explanation :
Power : It is defined a the rate of doing work per unit time.
Formula used :
where,
P = power
w = work done
t = time
Now we have to determine the rate of power for the following options.
(A) A machine does 200 joules of work in 10 seconds.
(B) A machine does 400 joules of work in 10 seconds.
(C) A machine does 200 joules of work in 5 seconds.
(D) A machine does 400 joules of work in 5 seconds.
From this we conclude that, a machine does 400 joules of work in 5 seconds has the highest rate of power.
Hence, the correct option is, (D)
Answer: D
Explanation:
When an object falls gravity is pulling down on it and is picking up speed, but as it gains speed air resistance becomes a faster. Air resistance increases with speed. And that force keeps it from accelerating eventually the object will pick up speed such that the force due to air resistance will keep it from getting any more speed at that point force due to air resistance is equal to its weight (mg) and the net force is equal to zero so it won’t accelerate any more at that point it is said to be moving in terminal velocity.
When an object has reached terminal velocity, it will have a constant velocity
Answer: 3.5 seconds
EXPLANATION:
Using the formula:
v = u + at
And taking the upwards direction as positive, we have the following information:
u = 35 m/s
a = -10m/s^2 (this is acceleration due to gravity)
At the top of its path, the apple will have a velocity of 0 m/s, therefore:
v = 0m/s
Once you substitute everything into the formula, you get:
0 = 35 + (-10)t
Therefore, t = 35/10 = 3.5 seconds
