Question

select the correct answer.
force due to
gravity = 12 n
applied
force = 20 n \tforce due to
\t\t\t\t\t\t\tfriction = 20 n
force exerted by
the ground
in the above diagram, the block is at static equilibrium on the ground. what is the value of the force exerted by the ground on the block if the force
due to gravity is 12 newtons?
a. 20 newtons
b. 12 newtons
c. -12 newtons
d. -20 newtons
e. 0 newtons

Explanation:

Step1: Recall Static Equilibrium in Vertical Direction

In static equilibrium, the sum of vertical forces is zero. The force due to gravity (downward) and the force exerted by the ground (upward) are vertical forces. Let \( F_{gravity} = 12\,\text{N} \) (downward, so we can take it as negative if upward is positive) and \( F_{ground} \) be the force exerted by the ground (upward, positive). The equilibrium condition is \( F_{ground}+(-F_{gravity}) = 0 \) (since gravity is downward, opposite to ground's force).

Step2: Solve for \( F_{ground} \)

From \( F_{ground}-F_{gravity}=0 \), we substitute \( F_{gravity} = 12\,\text{N} \). So \( F_{ground}=F_{gravity}= 12\,\text{N} \). The horizontal forces (applied force and friction) are equal and opposite, so they don't affect the vertical force balance.

Answer:

B. 12 newtons