Question

A block of rock with a mass of 72 kg slides on a surface inclined at an angle of 30° as shown in the figure. Assuming no cohesion and friction, the force \( F \) is ........... Newton (answer in one decimal place; acceleration due to gravity = 9.8 m/s²). 

 

Hint:

To calculate the force acting on an object on an inclined plane, use the component of weight parallel to the surface: \( F = m \cdot g \cdot \sin(\theta) \).

Answer 1

Correct Answer: 352.8

Step 1: Understand the problem setup.
The force \( F \) is the component of the weight of the rock that acts parallel to the inclined surface. The force is calculated as: \[ F = m \cdot g \cdot \sin(\theta) \] where \( m \) is the mass of the rock, \( g \) is the acceleration due to gravity, and \( \theta \) is the angle of inclination.

Step 2: Calculation.
Substitute the known values: \[ F = 72 \, \text{kg} \times 9.8 \, \text{m/s}^2 \times \sin(30^\circ) \] \[ F = 72 \times 9.8 \times 0.5 = 352.8 \, \text{N} \]

Step 3: Conclusion.
The force \( F \) is 352.8 N.