1. While chatting on his phone, Joe drives his car at a constant 32 m/s up a 20 ∘ bridge ramp, not realizing that the road was never finished. The road ends suddenly when it is a height 14.5 m above the ground. Ignore air drag.

What is the vertical component of the velocity of Joe's car the instant before it strikes the ground? Use up as the positive direction.

What is the horizontal component of the velocity of Joe's car the instant before it strikes the ground? Use right as the positive direction.

What is the speed of Joe's car the instant before it strikes the ground?

2. A student throws rocks from the roof of a building. All of the rocks are thrown with the same initial speed v0 and from the same initial height y0, but they are thrown with different angles with respect to the horizontal. Derive an expression for the minimum angle that the landing velocity of the rock can make with the horizontal.

The problem asks about the minimum angle at which the rock can strike the ground. If you sketched a good selection of trajectories, your diagram should help you see what determines this angle. To achieve the minimum final angle, at what initial angle θ0 (measured relative to the x axis) must you throw the rock?

Enter the angle in degrees. A rock thrown straight up has θ0=90∘; a rock thrown straight down has θ0=−90∘; a rock thrown horizontally has θ0=0∘. If the final angle does not depend only on the initial angle, type NA.

3. For the motion diagram given (Figure 1), sketch the shape of the corresponding motion graphs in Parts A to D. Use the indicated coordinate system. One unit of time elapses between consecutive dots in the motion diagram.

 

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