Answer:
Explanation:
Given that,
Number of extra electrons, n = 21749
We need to find the net charge on the metal ball. Let Q is the net charge.
We know that the charge on an electron is
To find the net charge if there are n number of extra electrons is :
Q = n × q
So, the net charge on the metal ball is
. Hence, this is the required solution.
The direction is the same as the direction the ball is moving in. Because of the rolling of the ball, the direction of movement of the surface of the ball is opposite the overall direction of the ball. Since friction will oppose the direction of movement of the surface of the ball, it is in the same direction as the net direction of movement of the ball.
Answer:
t = 4.1 seconds
Explanation:
It is given that,
Width of road which is to be crossed by a man is 8.25 m, it means it is distance to be covered.
Speed of man is 2.01 m/s
We need to find the time taken by the man to cross the road. It is a concept of speed. Speed of a person is given by total distance covered divided by time taken. So,

t is time taken

So, the time taken by the man to cross the road is 4.1 seconds.