Answer:
B is the answer
Explanation:
thank you I hope it helps you
A reference frame can be moving. To make sure that newtons laws still apply, the reference frame must not be accelerating.
Answer:
The bowling ball
Explanation:
The PE (gravitational potential energy) of an object is given by:
where
m is the mass of the object
g is the gravitational acceleration
h is the height of the object above the ground
In this case, we are comparing the PE of a bowling ball and of a ping pong ball. The two balls are located at same height (h=5 m) and the gravitational acceleration is the same (g=9.8 m/s^2), so their PE depends only on their mass: since the bowling ball has a greater mass than the ping pong ball, the bowling ball will have a greater PE.
Answer:
Well, the options are not given in the questions. But the correct option is:
"Gamma rays do not completely penetrate earth atmosphere."
Explanation:
Most of the gamma rays coming from the stars and sun can not penetrate the earth's atmosphere because atmosphere is as thick to the gamma rays as a 12 foot thick plate of aluminium. They rather absorb in the atmosphere and knock out electrons by reacting with the atoms and produce ions and electrons. These secondary ions and electrons then came to earth during rain fall. Due to this reason gamma ray telescope was not get funded for the study of black holes.
Let her initial velocity be U.
Let the width of the river be W.
She swims 3/5 the width of the river at U.
Remainder width = (1 - 3/5) = 2/5.
She then swims 2/5 the width with velocity U/2.
Average Speed = (Total Distance Traveled) / ( Total Time Taken).
Distance = Speed * time
time = Distance / Speed.
Time in first trip: = (3/5)W / U = 0.6W/U.
Time in second trip = (2/5)W / (U/2) = 0.4W / 0.5 U = 0.8W/U
Total Distance Traveled = W, width of the river.
Average Speed = W / (0.6W/U + 0.8W/U) = W / (1.4W/U)
= W * U / 1.4W
= U/1.4
= U * 10 / 14
= (5/7) U.
Therefore Average speed is (5/7) of the initial speed.
