The displacement in simple harmonic motion is a maximum when thea) acceleration is zero. d) kinetic energy is a maximum. b) velocity is a maximum. e) potential energy is a minimum. c) velocity is zero.

C) velocity is zero.

Explanation:

In a simple harmonic motion, the total mechanical energy of the system (which remains constant in absence of friction) is given by the sum of the elastic potential energy (U) and the kinetic energy (K) at any moment of the motion:

where

k is the spring constant

x is the displacement

m is the mass

v is the speed

Since E is a constant number, we immediately see from the formula that, when U increases, K decreases, and viceversa. Therefore, the maximum displacement (maximum x), which corresponds to the maximum potential energy U, will occur when K (kinetic energy) is zero. But K=0 means v=0, so when the velocity is also zero.

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards

the best answer for these questions would be:

1.            c. is smaller

2.            d) concrete operational

3.            b) interaction with the environment – the children interact with their environment can them learn more.

4.            a) parents who reason openly with children can limit a child’s cognitive ability.