Urgent what does newton's third law say about why momentum is conserved in collisions?

1. unequal forces act for unequal times, so the change in momentum for both objects must be unequal.

2. equal forces act in equal times, so the change in momentum for both objects must be equal.

3. equal forces act for unequal times, so the change in momentum for both objects must be equal.

4. unequal forces act for unequal times, so the change in momentum for both objects must be equal.

Asmall 21 kilogram canoe is floating downriver at a speed of 1 m/s. what is the canoe's kinetic energy?

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The base of a 50-meter tower is at the origin; the base of a 50-meter tree is at (0, 50, 0). the ground is flat and the z-axis points upward. the following parametric equations describe the motion of six projectiles each launched at time t = 0 in seconds. (i) r (t) = (50 + t2)k (ii) r (t) = 2t2 j + 2t2k (iii) r (t) = 50 i + 50 j + (50 − t2)k (iv) r (t) = 2t j + (50 − t2)k (v) r (t) = (50 − 2t) i + 2t j + (50 − t)k (vi) r (t) = t i + t j + tk (a) which projectile is launched from the top of the tower and goes downward? at time t = , the projectile hits the ground at point (x, y, z) = . (b) which projectile hits the top of the tree?