Answer:
Ball A
Explanation:
Let the initial speed of the balls be u .
Angle of projection for ball A = 20°
Angle of projection for ball B = 75°
As we know that at highest point, the ball has only horizontal speed which always remains constant throughout the motion because the acceleration in horizontal direction is zero.
Speed of ball A at highest point = u Cos 20° = 0.94 u
Speed of ball B at highest point = u Cos 75° = 0.26 u
So, the ball A has bigger speed than B.
Answer:

Explanation:
Let the child is moving with speed same as the speed of water flow
So here the position of child with respect to flow must be zero
And if the boat start at an angle with the vertical
so its relative speed with flow of water is given as


now the time to reach the child is given as

so now we have

So the time to catch the child is given as


So distance moved by it in 0.104 h
distance moved by the boat in upstream direction given as


In y direction the displacement of boat is

net displacement of the ball is given as



Answer:
The greater weight increases the terminal velocity by acting as an extra force against gravity and air resistance.
Answer:
B
Explanation:
The correct answer is B) have unlike charges. Since they are attracted to each other they have to be unlike