Three forces \( F_1 = 10 \,\text{N} \), \( F_2 = 8 \,\text{N} \), \( F_3 = 6 \,\text{N} \) are acting on a particle of mass \( 5 \,\text{kg} \). The forces \( F_2 \) and \( F_3 \) are applied perpendicularly so that particle remains at rest. If the force \( F_1 \) is removed, then the acceleration of the particle is:
A tennis ball is dropped on to the floor from a height of \( 9.8 \, \text{m} \). It rebounds to a height \( 5.0 \, \text{m} \). Ball comes in contact with the floor for \( 0.2 \, \text{s} \). The average acceleration during contact is ______ \( \text{ms}^{-2} \). (Given \( g = 10 \, \text{ms}^{-2} \))
