Question

a 10kg box is pulled up a ramp that is at an angle of 20 degrees with the horizontal if the pulling force of 70 N causes an acceleration of 2.0m/s^2 find the friction

Answer 1

Friction = 15.80 Newton

Step-by-step explanation:

given

A pulling force (F) is 70N acting on the block of 10kg (M) which is placed on the ramp which is at an angle of 20° with the horizontal.

Irrespective to the ramp ,Weight of the body acts vertically downward , if we resolve the components of W=Mg as Mgsin20° (along the ramp) and Mgcos20° (perpendicular to the ramp) as shown in the attachment which contains FBD of the block

as given the body is Accelerating with an acceleration (a) of 2 m/
`s^(2)` due to the pulling force . As friction always opposes the motion it acts in the backward direction to the pulling force .as shown in the figure attached

By Newton's 2nd Law

Ma = F - MgSin20°-friction

by subtituting the values we get

10(2) = 70 - 10(10)sin20° - friction

friction =70 - 100sin20° -20

friciton = 15.7979N

by rounding of ,

Frictional force is 15.80 Newton