Forces

The unit of force is N or _______

• kg ms^-1

• kg m s

• kg ms^-2

• kg m^-1 s

Which of the following is not correct about WEIGHT

• a vector quantity

• magnitude W = mg

• SI unit = Newton

• Direction always vertically upwards

Which of the following is not correct about TENSION?

• SI unit = kg m s^-2

• a scalar quantity

• direction is always outward from the body

• a vector quantity

Normal force ¡s a reaction force that exerted by the _________ to an object in contact with it.

• weight

• friction

• surface

• mass

Direction of normal force is always _________degree to the contact surface.

• 0

• 45

• 30

• 90

Friction is always opposite to the direction of _________.

• Force applied

• Normal force

• Motion

• Weight

______________ is the frictional force that exist between two objects when there is NO MOTION.

• Kinetic friction

• Static friction

Just before an object starts to slide, static friction , f_s is

• f_s < f_s(max)

• f_s > f_s(max)

• f_s = f_s(max)

Values of µs and µk depends on the nature of the surfaces in contact. In general,

• μ_k > μ_s

• μ_s > μ_k

Newton's 1st law states that an object at rest will remain at rest. Which represent the 1st law

• ∑F = ma

• F₁₂ = -F₂₁

• ∑F_x = ∑F_y =∑F_z = 0