Answer: Cluster 3 (D)
Explanation: Cluster 3 is the oldest and it could be the source from which cluster 2 and 3 got their spectral type from.
When you do work to lift the object, the amount of work you do BECOMES the object's gravitational potential energy. It GETS its potential energy from the work you do to lift it. They're equal. You lose it, and the object gains it. Energy is not created or destroyed. It's just transferred from you to the object.
Later, when you DROP the object, GRAVITY does the same amount of work on it, to pull it to the ground. Again, no energy is created or destroyed. Every time a force acts to move anything, the energy to do it comes from somewhere, and the energy goes somewhere.
Answer: 18.35 m/s
Explanation:
At the highest point of trajectory, the vertical component of the velocity would be zero and the tennis ball would have horizontal component of velocity.
It is given that the initial velocity of the ball is 32 m/s and it makes 35° with the vertical. Hence the horizontal component of the velocity,
v sin θ = 32 m/s × sin 35° = 18.35 m/s
Hence, at the highest point in its trajectory, the tennis ball would be moving with the speed 18.35 m/s.
