If the angle is either 0 or 180, that means that there is either negative or positive work, so A and D are not correct.
If the angle is 45, then there is still some work involved.
The only option where there is no work done by a force is B. when the angle is between the force and displacement is 90.
Answer:
30Km/h
Explanation:
acceleration is the change of speed in a given time so when we substract the accelerations we can know how much the car goes per an hour
Solution: From the given question, we shall find the vector quantity among the
(A) Time , (B) Velocity, (C) Distance , (D) Speed
Concept: <u>Vector Quantity: </u>All those physical quantities which have magnitude as well as specific directions, are called Vector Quantities.
Here, Time, Distance and Speed have only magnitude but have no directions so they will be scalar quantities.
Now, <u>Velocity:</u> It is defined as the change in displacement per unit time. Since the change in the displacement will be in particular direction only. Hence, velocity will be the vector quantity.
Hence, the option (B) Velocity will be the correct option.
Answer :
.
Explanation:
It is given that,
Electric field strength, 
We know that,
Charge of electron, 
Mass of electron, 
From the definition of electric field,
...............(1)
According to Newton's second law, F = ma..........(2)
From equation (1) and (2)




or

So, the horizontal component of acceleration of an electron is
.
Hence, it is the required solution.