Dolphins and other sea creatures can leap to great heights by swimming straight up and exiting the water at a high speed. A 200 kg dolphin leaps straight up to a height of 7.8 m . When the dolphin reenters the water, drag from the water brings it to a stop in 1.8 m . Assuming that the force of the water on the dolphin stays constant as it slows down.

a. How much time does it take for the dolphin to come to rest?
b. What is the force of the water on the dolphin as it is coming to rest?

Answer8.0m;

    m₁v₁ + m₂v₂ = (m₁ + m₂)vmomentum is conserved.the left-hand side of the equation represents the momentum in the system before the collision.the right-hand side represents the momentum in the system after the collisionm₁ and v₁ represents the mass and the velocity of the physics blockm₂ and v₂ represents the mass and velocity of the ball of puttyv represents the final velocity of the combined mass.the question states the two masses stick together. they combined mass has its own velocity with the body mass the sum of the two objects' massestheir combined momentum is (m₁ + m₂)vto find the magitude of (m₁ + m₂)v, we need to add the vectors on the left-hand side of the equation: m₁v₁ + m₂v₂.note the diagram. i have positioned the vectors in accordance with their directions.the magnitude of the resultant can be calculated using the pythagorean theorem since this is a right triangle situation (north and west are perpendicular)|(m₁ + m₂)v| =  √[ (m₁v₁)² + (m₂v₂)² ]|(m₁ + m₂)v| =  √[ (1.5kg·8.0m/s)² + (0.40kg·20m/s)² ]|(m₁ + m₂)v| =  14.4 kg m/sfor two significant figures (assuming that 20m/s is two), this rounds to 14 kg m/s

Ibelieve the answer is either b or c, but i'm leaning more towards c.hope my answer has you : )