Question

Find the minimum force needed to move a body weighing 50 kg along a horizontal surface with a uniform velocity. If the coefficient of kinetic friction is 0.5.​

Answer 1

Answer:

• Minimum force required to move the body = 245 N

Explanation:

Given:-

• Mass of body placed along a horizontal surface, m = 50 kg
• coefficient of Kinetic friction, μ = 0.5

To find:-

• The minimum force needed to move the body with uniform velocity, F =?

Formula required:-

• Formula for normal reaction when vertical forces are equilibrium

        R = mg

• Formula for friction force

        f = μ R

[ where R is normal reaction, m is mass of body, g is acceleration due to gravity, f is friction, μ is coefficient of friction ]

Solution:-

Calculating the normal reaction on the body

→ R = mg

→ R = 50 × 9.8

→ R = 490 N

Now, calculating the friction acting on the body

→ f = μ R

→ f = 0.5 × 490

→ f = 245 N

Friction force acting of the body is 245 N., it means we need a force that can overcome this friction. Hence,

• Minimum force required to move the body is 245 Newton.

Answer 2

${\bold{\sf{\underline{Understanding \: the \: question}}}}$

➨ This question says that we have to find the minimum force needed to move a body whose mass is 50 kg , along a horizontal surface with a uniform velocity. And now this question says that if the coefficient of kinetic friction is 0.5 then we have to find the minimum force needed to move this body.

${\bold{\sf{\underline{Given \: that}}}}$

➨ Mass of the body along a horizontal surface with a uniform velocity = 50 kg

➨ The coefficient of kinetic friction is 0.5

${\bold{\sf{\underline{To \: find}}}}$

➨ Minimum force needed to move the given body.

${\bold{\sf{\underline{Solution}}}}$

➨ Minimum force needed to move the given body = 245 N

${\bold{\sf{\underline{Using \: concepts}}}}$

➨ Formula to find the frictional force.

➨ Formula to find the normal reaction, when the vertical force are equilibrium

${\bold{\sf{\underline{Using \: concepts}}}}$

➨ Frictional force => f = μR

➨ The normal reaction, when the vertical force are equilibrium => R = mg

${\bold{\sf{\underline{These \: also \: mean}}}}$

➨ f means friction force

➨ μ means friction's cofficient

➨ R means reaction ( normal )

➨ m means mass

➨ g means acceleration due to gravity.

➨ Unit of force is N ( Newton )

${\bold{\sf{\underline{Full \: solution}}}}$

~ Finding normal reaction, when the vertical force are equilibrium

➥ R = mg

➥ R = 50(9.8)

➥ R = 50 × 9.8

➥ R = 490 Newton

Note : We write 9.8 here because we already know that the gravity is mostly written as 9.8 m/s. Means 9.8 is it's value.

~ Frictional force

➥ f = μR

➥ f = 0.5(490)

➥ f = 0.5 × 490

➥ f = 245 Newton

• Henceforth, 245 N is the minimum force needed to move the given body.