Answer:
50 N
Explanation:
Since the refrigerator doesn’t move, that means the force of friction equals the amount of force the child exerts on the fridge. If the friction force were greater than the force by the child, the fridge would start accelerating towards the child. If it were less than the force the child exerted, the fridge would start accelerating away from the child. Therefore, the net force must be 0, in this case, the friction force is equal to the force the child exerted, for it to stay at rest (as Newton’s First Law stated).
I hope this helps! :)
B. Polar Molecule
Explanation - polar means that the electrons are not shared evenly. Water (H2O) has two Hydrogen atoms which are positive because they give their electrons away, and one Oxygen atom which is negative because it received the electrons
You want all those boxes filled in (0,0)
Because the air inside the tires is kept at high pressure.
In fact, the force applied by the tires upwards to counter-balance the weight of the car (pushing downwards) is

where p is the pressure of the air inside the tires and A is the area of contact between the tire and the car. Therefore, a higher pressure means a larger force F, and eventually if the pressure p is higher enough the force F will be large enough to counterbalance the weight of the car.