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Is fired horizontally with a velocity of 98 metre per second from the top of the hill 490 metre high find the velocity with which projectile strikes the ground? |
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Answer» Figure of the projectile motion in the attachment.The initial velocity of the BODY = 98 m/s.The HEIGHT of the hill = 490 m.Find the velocity at which the body STRIKES the ground = ?Finding the time :⇒ s_y = (u_y)t + ½(a_y)t²⇒ 490 = 0 + ½(9.8)(t²)⇒ t = 10 sWe know that, v_x = u_x + (a_x)t⇒ v_x = 98 + 0 = 98 m/sAnd, v_y = u_y + (a_y)t⇒ v_y = 0 + (9.8)(10) = 98 m/sSo, v = √[(v_x)² + (v_y)²]⇒ v = √(98)² + (98)²⇒ v = 98√2 m/sHence, the speed at which the body will strike the ground = 98√2 m/s. |
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