Question

A block of mass Mis pulled on a smooth horizontal table by a string making an angle with the horizontal as shown in figure if the acceleration of the block is a find the force applied by the table on the block

a. 2Mg-Ma tan
b. Mg- tan
c. ma/cos
d. Ma/sin​

Answer 1

Given info : A block of mass Mis pulled on a smooth horizontal table by a string making an angle θ with the horizontal as shown in figure.

To find : if the acceleration of the block is a, the force applied by the table on the block is ...

solution : let T is tension acting on the string and N is normal reaction acting on the block by the table.

as string is making an angle θ with the horizontal.

so, horizontal component of T = Tcosθ

vertical component of T = Tsinθ

at equilibrium,

net horizontal force = Ma

⇒Tcosθ = Ma

⇒T = Ma/cosθ ...(1)

similarly, net vertically upward force = weight

⇒Tsinθ + N = Mg

from equation (1) we get,

Masinθ/cosθ + N = Mg

⇒N = Mg - Ma tanθ

Therefore the force applied on the block by the table is (Mg - Ma tanθ).