What is the difference between mass and momentum?

Answer & Explanation:

Definition:

Mass informs us about how much matter is present in a body. It is the measure of the inertia of a body. It can be measured by measuring the force of gravity acting on it on earth.

On the other hand, Momentum is the quantity of motion of the body. It depends depends upon velocity and the direction of the motion of the body.

Unit:

The SI unit of mass is kilogram (kg) while the SI unit of momentum is kg.m.s-1.

Formula:

Mass = Momentum / Velocity

Momentum = Mass * Velocity

or p = mv

Type:

Mass is scalar quantity while Momentum is a vector quantity.

The motion of an elevator accelerating downwards, makes the passengers feel lighter, and when accelerating upwards, the passengers feel heavier

The elevator's velocity 6.0 s after starting is approximately 3.283 m/s

The reason the above value above value is correct is given as follows:

The known parameters:

Henry's mass, m = 95 kg

After the elevator starts moving;

The reading on the scale for the first 3.0 seconds = 830 N

The reading on the scale for the next 3.0 seconds = 930 N

Required:

The velocity of the elevator 6.0 s after starting

Solution:

Weight = mass × Acceleration due to gravity

Henry's weight, W = 95 kg × 9.8 m/s² ≈ 930 N

The apparent weight in downward motion is less than the weight

With regards to the weight, W, we have;

Therefore;

In the first 3 seconds, we have;

In the next 3 seconds, we have;

Which gives;

v = u + a·t

u = 0

The velocity after the first 3 seconds, v₃, is given as follows;

v₃ = 0 + 1.073 m/s² × 3.0 s ≈ 3.22 m/s

v₃ ≈ 3.22 m/s

The velocity after the next 3 seconds, (t = 3), v₆, is given as follows;

v₆ = v₃ + × 3

∴ v₆ ≈ 3.22 + 0.021 × 3 = 3.283

The elevator's velocity 6.0 s after starting, v₆ ≈ 3.283 m/s

Learn more about motion in an elevator here:

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