The answer is actually 1 & 17, maybe you meant to put 1&17 as option b
consider the velocity of the ball towards the wall as negative and away from the wall as positive.
m = mass of the ball = 513 g = 0.513 kg
v₀ = initial velocity of the ball towards the wall before collision = - 14.7 m/s
v = final velocity of the ball away from the wall after collision = 11.3 m/s
t = time of contact with the wall = 0.038 sec
F = average force acting on the ball
using impulse-change in momentum equation , average force is given as
F = m (v - v₀)/t
inserting the values
F = (0.513) (11.3 - (- 14.7))/0.038
F = 351 N
Answer:
The speed of the ball is approximately 5.94 m/s
The Tension of the string at the bottom is 3.92 N
Explanation:
We need to find the speed of the ball, which is constant due to the fact that we are in a uniform circular motion. Notice as well that the speed of the ball is the magnitude of the tangential velocity "
" (vector that changes direction with the position of the ball but doesn't change magnitude in this case).
We analyze first the top position of the circular motion, for which information on the tension of the string is given (see first free body diagram in the attached picture). We are told that the tension at the top of the movement equals twice the force of gravity on the ball's mass: T - 2*m*g = 1.96 N. And we know that there are two forces acting on the ball in that position (illustrated with the green arrows pointing down): one is the ball's weight due to gravity, and the other is the string's tension. So we can write Newton's second law for this situation:

Newton's second law tells us that the net force should equal the mass of the ball times its acceleration (F = m * a), and in this motion, the acceleration is the centripetal acceleration. Therefore weuse this equation to solve for the centripetal acceleration of the ball:

The centripetal acceleration is defined as the square of the tangential velocity divided the radius of the circular motion. Then we use it to derive the magnitude of the tangential velocity (speed of the ball):

So we have found the speed of the ball.
Now we focus our attention to the bottom of the motion, and again use Newton's second law to solve for the string tension (see second free body diagram in the attached picture).
We notice here that the tension and the weight are acting in opposite directions, so we have such into account when finding the net force on the ball, and then solve for the tension knowing the value of the centripetal acceleration (recall that the magnitude of the tangential velocity is the same because of the uniform circular motion).

Answer:
a. The east end of the rod is at higher potential than the west end.
Explanation:
The horizontal rod is oriented in the east-west direction. This means that applying right hand rule, the current will flow from the east to the west. Now, if we assume tat it is a closed loop, we know from polarity of voltage that current usually flows positive to negative terminal within a circuit.
This means the east is at a largely positive terminal while the west is at a largely negative terminal.
Thus, we can say that the east end of the rod is at higher potential than the west end of the rod.
Answer:v
Explanation:
Given
Initially spring mass system is moving towards right with velocity 
Now if the spring is released left block moves towards left with a velocity 
As there is no external force applied on the system therefore the change in linear momentum is zero i.e. it is conserved
so center of mass continue to move towards the right with velocity v or we can say right block moves towards right with velocity
and left block moves with velocity 