Question

Two particles A and B start simultaneously from a Point P with velocities 20 m/s and 30 m/s respectively. A and B move with acceleration equal in magnitude but opposite in direction. When A overtakes B at Q, its velocity is 30 m/s. The velocity of B at Q :

Answer 1

Answer:

20 m/s

Explanation:

Given

• u(A) = 20 m/s
• u(B) = 30 m/s
• acceleration equal in magnitude but opposite in direction

Solving

• Velocity of A at Q = 30 m/s
• From, P to Q, Δv(A) = 30 - 20 = +10 m/s
• Therefore, velocity of B at Q will be decreased by 10 as it is equal in magnitude but opposite in direction to A
• Δv(B) = v(B at Q) - u(B at P)
• -10 m/s = v(B at Q) - 30 m/s
• v(B at Q) = 30 - 10 = 20 m/s