A cyclist riding in a straight line has an initial velocity of 3.5 m>s, and accelerates at -1.0 m>s2 for 2.0 s. The cyclist thencoasts with zero acceleration for 3.0 s, and finally accelerates at 1.5 m>s2 for an additional 2.0 s. (a) What is the finalvelocity of the cyclist? (b) What is the average acceleration of the cyclist for these seven seconds?P

A human being cannot tolerate acceleration of much more than a few hundred m/s2 without sustaining serious permanent injury. If the acceleration is sustained for more than a few seconds, the maximum tolerable acceleration is much less. Suppose a car is initially moving at 32.7 m/s and then is quickly stopped in a collision. (a) What is the minimum time over which the driver must be decelerated in order that he not experience an acceleration of magnitude greater than 9.90 101 m/s2? Assume constant acceleration. (b) What is the minimum distance the driver must be allowed to move forward during the deceleration? (Air bags are an improvement over seat belts because the distance the driver moves forward is greater with a compressible air bag than with a seat belt. This does not mean, however, that you would want to move forward in the car without air bags.)

A particle has an acceleration of + 6.24 m/s2 for 0.300 s. At the end of this time the particle’s velocity is + 9.31 m/s. (a) Write given quantities.  (b) Calculate the particle’s initial velocity.

From t = 0 to t = 4.59 min, a man stands still, and from t = 4.59 min to t = 9.18 min, he walks briskly in a straight line at a constant speed of 1.22 m/s. What are (a) his average velocity vavg and (b) his average acceleration aavg in the time interval 1.00 min to 5.59 min? What are (c) vavg and (d) aavg in the time interval 2.00 min to 6.59 min?

A jogger jogs from one end to the other of a straight track in 1.08 min and then back to the starting point in 1.53 min. What is the jogger's average speed at the following points? (Assume the track is 100 m long.)  a in jogging to the far end of the track (b) coming back to the starting point (c) for the total jog

The froghopper Philaenus spumarius is supposedly the best jumper in the animal kingdom. To start a jump, this insect can accelerate at 4.00 km/s2 over a distance of 2.0 mm as it straightens its specially designed "jumping legs." (a) Find the upward velocity with which the insect takes off. m/s (b) In what time interval does it reach this velocity? ms (c) How high would the insect jump if air resistance were negligible? The actual height it reaches is about 70 cm, so air resistance must be a noticeable force on the leaping froghopper. m Need Help? Read It

On a 200 km bike cycle ride, you ride the first 90 km at an average speed of 20 m/s. What mustyour average speed over the next 40 km be to have your average speed for the total 200 km be?(b) Given this average speed for the first 90 km, can you possibly attain an average speed of80 m/s for the total 200 km ride? Explain.

A spaceship starts at rest, and then launches vertically into the air with an upward acceleration of 2.0 m/s2. When it reaches a height of 500 m, it runs out of fuel; after this point its acceleration is due to gravity, i.e. 9.8 m/s2 downward. (ignore air resistance)(a) How long does it take the spaceship to run out of fuel? (b) What is its velocity at the point when it runs out of fuel? (c) What is the maximum height that the spaceship reaches? (d) For how much time (total, from launch) is the rocket in the air? (e) What is the spaceship’s velocity just before it hits the ground?

A person walks first at a constant speed of 4.90 m/s along a straight line from point to point and then back along the line from to m/s. (a) What is her average speed over the entire trip? m/s (b) What is her average velocity over the entire trip? m/s @ at a constant speed of 3.10

A ball of moist clay falls 17.7 m to the ground. It is in contact with the ground for 21.0 ms before stopping. (a) What is the average acceleration of the ball during the time it is in contact with the ground? (Treat the ball as a particle.) (b) Is the average acceleration up or down?