1.1. A student draws a Newton's third law pair of forces on a book, as shown in Figure 1.

Figure 1

F_g is the gravitational force and F_N is the normal reaction force.

State and explain whether the student has drawn a Newton's third law pair of forces correctly.

1.2. A child balances on a pogo stick as shown in Figure 2. The child and the pogo stick are both stationary.

Figure 2

Using Newton's second and third laws, explain how the child moves upwards when they exert a downward force on the spring.

1.3. Explain, using Newton's Third Law, how the forces on a person's foot enables them to walk on the ground.

1.4. A teacher is running late for a class. He sets off and exerts a force of 8.5 N on the ground. 

The mass of the Earth is 6.0 × 10²⁴ kg.

Calculate the theoretical acceleration of the Earth resulting from this step. Give your answer to 2 significant figures.