
Actually Welcome to the Concept of the Electrostatics.
Basically here we can see that, the Negative test charge usually a Electron is facing a force from the right side, this we can say that a Electric field as like charge is creating a repulsive force from the right to left side.
thus,
1) The electric field points to the left because the force on a negative charge is opposite to the direction of the field.
serving speed = 170 km/h
now we will convert it into m/s

now it will have two components along x and y directions

also in x and y directions we know





by solving above equation we have


so angle is 6.11 degree below the horizontal
now we have


now time taken by ball to reach the ground will be


now the displacement in x direction will be


now the distance from net will be

So it will land inside the line
Answer:
The speed of the bob when it passes the lowest point 
Explanation:
Given data

When a pendulum swinging back & forth then at highest point the velocity is zero and lowest point velocity is maximum.
Velocity at lowest point is given by



Therefore the speed of the bob when it passes the lowest point 
Answer:B,C,D
Explanation:
Thermodynamic efficiency is given by

efficiency can be increased by Keeping
constant and increasing 
Keeping
constant and decreasing
by increasing 
by decreasing
ratio