Question

A ball is rolled off the edge of a horizontal table at a speed of 4 m/s. It hits the ground after 0.4 sec. Which statement given bellow is true ?

• A. It hits the ground at a horizontal distance 1.6 m from the edge of the table
• B. The speed with which it hits the ground is 4.0 m/s
• C. Height of the table is 0.9 m
• D. It hits the ground at an angle of 60⁰ to the horizontal

Answer 1

Answer: (A)

It hits the ground at a horizontal distance 1.6 m from the edge of the table

Answer 2

\ R = u.T = 4 × 0.4 = 1.6 m

v_y = gT = 4 m/s

\ v = $\sqrt { v _ { x } ^ { 2 } + v _ { y } ^ { 2 } }$ = $4 \sqrt { 2 }$ m/s

H = $\frac { 1 } { 2 }$ gT² = $\frac { 1 } { 2 }$ × 10 × (0.4)² = 0.8 m

tan a = $\frac { v _ { y } } { v _ { x } }$ = 1 ̃ a = 45⁰