Problem 5.20

First draw the figure and think of the forces acting on the surfer.
The weight of the surfer is acting straight down, the normal force of the wave
on the surfer is perpendicular to the direction of motion.

Choose the x-axis as the plane the surfer is moving in. Apply Newton's second law along this direction.

Problem 3.28

To input the unit vector simply click on the left most button right above the equation. Then click on the button with a box and ^ symbol on top.

Problem 2.53

For part D.

The key is to break the motion into two parts. The first part is during the reaction time. In this time the car moves at constant velocity (it has not began decelerating yet). The second part of the motion is when the person steps on the brakes. In this case you have a constant negative acceleration until the car stops.

Find the distance traveled during each segment and the sum should add to the given 55m.

Label the reaction time with a variable T, and then solve for T in the above equation.

Problem 2.22

Part C asks for AVERAGE SPEED.

Hint: Average speed = total distance traveled/time elapsed.
So you have to look at the graph and estimate the total distance traveled in the given time
in the one second interval.

Problem 2.60

Before you do this problem make sure to go over the cop/speeder problem that we did in class.

The only difference here is that the bicycle which passes the stationary bicycle moves an EXTA 2 seconds. So you have to account for this extra 2 seconds in the equation for distance traveled.

Your final equation will be a quadratic equation, which you should be able to solve.

Problem 2.22

For this problem you have to plot the graph for ALL tick marks along the t-axis.
This is a total of 11 points. So just calculate x vs t at each interval.