Question

1.
A 20 kg block is in motion on a rough horizontal surface A horizontal force of 60N is required to
keep the body moving with constant speed. The coefficient of kinetic friction is (g = 10 ms )
a) 0.3
b) 0.4
c) 0.2
d) 0.5
​

Answer 1

Answer

Given -

$F_k$ = 60N

m = 20 kg

g = 10 m/s²

where -

$\longrightarrow$$F_k$ is the kinetic friction.

$\longrightarrow$m is mass of body.

$\longrightarrow$g is acceleration due to gravity.

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To find -

Coefficient of kinetic friction $\longrightarrow$$\mu$

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Formula used -

$\boxed{\bf \red {F_k = \mu N}}$

$\boxed{\bf \pink {N = mg }}$

where

$\longrightarrow$$F_k$ is the kinetic friction.

$\longrightarrow$m is mass of body.

$\longrightarrow$g is acceleration due to gravity.

$\longrightarrow$N is normal force.

$\longrightarrow$$\mu$ is Coefficient of kinetic friction

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Solution -

m = 20 kg

g = 10 m/s²

$\bf \red{N = mg}$

$\implies$$\bf N = 20 \times 10$

$\implies$$\bf N = 200$

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$F_k$= 60N

N = 200

$\bf \red{F_k = N \mu}$

$\implies$$\bf 60 = 200 \mu$

$\implies$$\bf \mu = \frac{200}{60} = 0.3$

Coefficient of static friction = 0.3

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Thanks

Answer 2

20 kg block is in motion on a rough horizontal surface A horizontal force of 60N is required to

keep the body moving with constant speed. The coefficient of kinetic friction is (g = 10 ms )

a) 0.3

b) 0.4

c) 0.2

d) 0.5

a is correct