1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

# A solid cube of mass 5 kg is placed on a rough horizontal surface, in xy-plane as shown. The friction coefficient between the surface and the cube is 0.4. An external force →F=3^i+4^j+20^k N is applied on the cube. (use g=10m/s2)

A
The block starts slipping over the surface
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
The friction force on the cube by the surface is 5 N.
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
The friction force acts in xy-plane at angle 127 with the positive x-axis in clockwise direction.
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
The contact force exerted by the surface on the cube is 925N
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution

## The correct options are B The friction force on the cube by the surface is 5 N. C The friction force acts in xy-plane at angle 127 with the positive x-axis in clockwise direction. D The contact force exerted by the surface on the cube is √925NFirst of all, lets calculate the maximum value of friction force on the cubefmax=μmg = 0.4x5x10 = 20 NThe friction force is acting in the xy-plane because the solid cube is resting on the same plane. Now, calculate the external force acting in the xy-planeFxy=√(32+42) = 5 NThe applied external force (Fxy) is less than the maximum value of friction force.Therefore, friction force acting on the cube will be equal to the external force.f=Fxy = 5 NThe external force is making 530 with x-axis, and we know that the friction force acts in the opposite direction of it.So, the angle made by the friction force will be 1800−530=1270 with the positive x-axis and in clockwise direction.Furthermore, the contact surface will exert two forces on the cube.(a) Friction force = 5 N in the xy-plane(b) mg−20 in the positive z direction =5x10−20 =30 NResultant contact force exerted by the surface =√(frictionforce2+(mg−20)2) =√(52+302) =√(925) NOption B, C, and D are the correct choices.

Suggest Corrections
0
Join BYJU'S Learning Program
Related Videos
Losing Weight Using Physics
PHYSICS
Watch in App
Explore more
Join BYJU'S Learning Program