Question

A sled having a certain initial speed on a horizontal surface comes to rest after traveling 10 m. If the coefficient of kinetic friction between the object and the surface is 0.20, what was the initial speed of the object

Answer 1

the initial speed of the object is 6.26 m/s

Step-by-step explanation:

given information:

distance, s = 10 m

the coefficient of kinetic friction, μ = 0.2

we use the equation where the kinetic energy is equal to the friction force.

kinetic energy, KE =
`(1)/(2) mv^(2)`

friction work, W = F(friction) s

KE = W

`(1)/(2) mv^(2)` = F(friction) s

where, F(friction) = μ N, N is normal force (N = m g)

= μ m g

so,

`(1)/(2) mv^(2)` = μ m g s

`(1)/(2) v^(2)` = μ g s

`v^(2)` = 2 μ g s

= 2 (0.2) (9.8) (10)

= 39.2

hence,

v =
`√(3.92)`

= 6.26 m/s