Question

Mark the correct option. If a ball is projected with velocity ${{v}_{o}}$ at an angle of elevation 30?, then

• A. gravitational potential energy will be minimum at the highest point of the trajectory
• B. kinetic energy will be zero at the highest point of the trajectory
• C. vertical component of momentum will be conserved
• D. horizontal component of momentum will be conserved

Answer 1

Answer: (D)

horizontal component of momentum will be conserved

Answer 2

Horizontal and vertical components of velocity in projectile motion are ${{u}_{x}}=u\cos \theta$ ${{u}_{y}}=u\sin \theta$ So, horizontal and vertical components of momentum are ${{p}_{x}}=mu\,\cos \theta$ ${{p}_{y}}=mu\text{ }\sin \theta$ At the highest point of its path, the vertical component of momentum becomes zero but horizontal component remains same. So, horizontal component of momentum will be conserved.