Question

A track athlete throws a discus that has a momentum of 42kg*m/s into a field with a velocity of 21 m/s. What is the mass of the discus? *
2 points

Answer 1

Given :

Momentum of disc = 42 kg m/s

Velocity of disc = 21 m/s

To Find :

Mass of the disc.

Solution :

❖ Momentum is defined as the product of mass and it's velocity$.$

Mathematically, p = m × v

• p denotes momentum
• m denotes mass
• v denoted velocity

➛ It is a vector quantity having both magnitude as well as direction.

➛ It can be positive, negative or zero.

➛ SI unit : kg m/s or N s

By substituting the given values;

➙ p = m × v

➙ 42 = m × 21

➙ m = 42/21

➙ m = 2 kg

∴ Mass of the object is 2 kg.

Knowledge BoosteR :

• As per newton's second law of motion, force is measured as the rate of change of linear momentum.
• Formula : F = dp / dt

Answer 2

Answer:

Question

A track athlete throws a discus that has a momentum of 42kg*m/s into a field with a velocity of 21 m/s. What is the mass of the discus?

Given

• momentum (p) = 42 kg.m/sec
• velocity (v) = 21 m/sec

To find

Mass of the object

solution

✏️The momentum of a body is defined as the product of its mass and velocity.

${ \underline{ \boxed{ \sf{ \large{p = m \times v}}}}}$

where

• p denotes momentum
• m denotes mass
• v denotes velocity (or speed ) of the body

subsitute the value in the formula

$\sf{ \to \:m = \frac{p}{v} } \\ \\ \sf{ \to \: m = \frac{42}{21} } \\ \\ \sf{ \to \: m = 2kg }$

→Therefore the mass of the object is 2 kg.

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MORE TO KNOW

✏️ Momentum is a vector quantity ( have both direction and magnitude )

✏️SI unit of Momentum is kilogram metres per second which can be written as kg.m/sec.

✏️Momentum depends upon the mass and the velocity of a body

✏️Force required to stop a moving body is directly proportional to its mass.

✏️Force required to stop a moving body is also directly proportional to the velocity of the body.

✏️If the body is at rest, its velocity is zero then it's momentum will also be zero.

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