Answer: The average velocity is 150 km/h
Explanation: 70+80=150
<span>A motor produces less mechanical energy than the energy it uses because the motor looses some energy to heat.</span>
Answer:
The angle between the electric field lines and the equipotential surface is 90 degree.
Explanation:
The equipotential surfaces are the surface on which the electric potential is same. The work done in moving a charge from one point to another on an equipotential surface is always zero.
The electric field lines are always perpendicular to the equipotential surface.
As

For equipotential surface, dV = 0 so

The dot product of two non zero vectors is zero, if they are perpendicular to each other.
The normal force is always perpendicular to the surface. So it would be straight to the left of the wall