Question

1.pre lab question

a- Write down Newton’s 3rd Law of Motion.

b- Suppose a small car collides with a truck that has a mass five times larger. Is the force the car does on the truck smaller, the same or larger than the force the truck exerts on the car. Justify your answer.

c- Write down the definition of momentum.

d- What is the relationship between the impulse and the change in momentum of an object?

Answer 1

Part-a

The Third Law of Motion indicates that when one object exerts a force on another object, the second object instantaneously exerts a force back on the first object. These two forces are always equal in magnitude, but opposite in direction. These two forces are called action and reaction forces.

Hence "For every action, there is equal and opposite reaction". This is the Newton's third law of motion.

Part-b

According to the above definition we can say that the force exert by the truck on car will be of equal magnitude that car exerts on the truck but is in opposite direction. The size of the given truck is irrelevent because it exerts force on earth in downward motion and earth exerts equal and opposite force on it in upward direction wheres as the force exerted by car is in horizontal direction, therefore we can clearly see that the force exerted by the truck is of equal magnitude or same as the force exerted by the car on the truck.

Part-c

Momentum can be defined as “mass in motion.” All objects have mass therefore if an object is moving, then it has momentum. A mass unit is multiplied by a velocity unit to provide a momentum unit.

  

The momentum of an object is equal to the mass of the object times the velocity of the object. Where momentum is denoted as “p”, mass is denoted with “m” and velocity is denoted with “v”.

Part-d

The impulse-momentum theorem states that the change in momentum of an object equals the impulse applied to it.

Impulse is a quantity that describes the effect of a net force acting on an object (a kind of "moving force").

therefore