A ball is projected horizontally from the top of a cliff on the surface of the earth with a speed of 40 ms-1. Assuming that there is no air resistance, what will be its speed after 3s?
Correct answer: C. 50 ms-1
- A. 30 ms-1
- B. 40 ms-1
- C. 50 ms-1
- D. 60 ms-1
Explanation
The horizontal component of velocity remains constant throughout the motion, vertical component is initially zero. The value of vertical component after 3s can be calculated using equation V = U + at Where V is the final velocity after 3s and U is the initial velocity which is zero. Substitute only y-components in this equation.V = U + at V = 0 + (10)(3)V = 30 m/sHorizontal component is 40 m/s and vertical is 30 m.sCalculate the velocity using the formula V = √[(V2x) + (V2y)]V = √(302)(402)V = √(900 + 1600)V = √2500V = 50 m.s
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Displacement, velocity and acceleration describe motion, including the horizontal and vertical components of projectile motion. The chapter connects these quantities with Newton's laws, momentum and impulse, then applies conservation of momentum to collisions, distinguishing elastic collisions from inelastic ones.
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