Question

2. When the plate begins to fall, the net force on the plate is? Select those that are valid.

a. zero

b. it's not zero

c. is directed upwards

d. it is directed downwards

e. it is directed to the right

3. As the plate falls, the force that increases is:

a. none

b. net force

c. normal force

d. air resistance

e. the weight

4. As the plate falls, the decreasing force is:

a. none

b. net force

c. normal force

d. air resistance

e. the weight

5. As the plate falls, what parameters are affected?

a. acceleration decreases, speed decreases

b. acceleration increases, speed increases

c. acceleration decreases, speed increases

d. acceleration increases, speed decreases

e. acceleration and speed are zero

Answer 1

2. As the plate falls, net force is in downward direction, and is non zero. Therefore option b and d are correct.

3. Usually the drag forces, like air resistance are proportional to the speed, so as the plate falls it's speed increases which increases the air resistance. Option d is correct.

4. There are two forces acting on the plate as it falls, one is gravity(weight) other is air resistance. Weight is fixed and air resistance increases. Therefore option a is correct.

5. As the plate falls, the acceleration is downwards so it's speed increases, because of it the air resistance which is acting upwards increases which reduces the net force downwards hence acceleration decreases. Therefore option c is the correct one.