Chapter 2, Problem 67P

In coming to a stop, a car leaves skid marks 77 mm long on the highway.   Assuming a deceleration of 4.30 m/s2m/s2 , estimate the speed of the car just before braking. Express your answer using two significant figures.

A kicker kicks a football upward from the ground at an initial velocity of 63 feet per second. The height of the football stadium is 70 feet. The height an object reaches with respect to time is modeled by the following equation: gr +vt +s In the equation, g is -32 ft/sec', v is the initial velocity, s is the initial height, and t is time in seconds. Write a function that models this situation as related to the number of seconds since kickoff. 1. 2. Sketch and describe the graph of this function, including intercepts and maximum height. 3. At what times is the football the same height as the stadium? Explain your answer. 4. Suppose the initial velocity of the kicked football is 68 feet per second. At what times is the football the same height as the top of the stadium? Justify your answer. Now consider that the kicker is trying to kick an extra point. A linebacker on the opposing team has a maximum reach of 10 feet, which includes his height, full extension of his arms, and his…

A pumpkin is shot straight up with an initial speed of 5.9 m/s. What is the maximum height it can reach, in meters? Use g = 10 m/s2.Your answer needs to have 2 significant figures, including the negative sign in your answer if needed. Do not include the positive sign if the answer is positive. No unit is needed in your answer, it is already given in the question statement.

acceleration ++++ time (a) (b) (c) Fig. 3.10 Graphs describing a body moving with constant positive acceleration: (a) acceleration versus time, (b) velocity versus time, and (c) position versus time speed (m/s) What Have I Learned So Far? Consider the given graph of speed versus time shown here. Then find the values of the following: 1 1. The acceleration from 0 s to 2 s 2. The acceleration from 2 s to 3 s 3. The acceleration from 5 s to 7 s 4. The distance traveled by the body from the 2nd to the 3rd second 5. The distance traveled by the body from the 5th to the 7th second 2 0 -1 veloci -2 momen time 1 2 3 posi bado 30.20 onit 4 time, (s) 5 time 6 Or [16] Menin qui grovdi 7 Moleto obsaheb Mied (20 od s volano tesi vor to szli nie The Physics of Point Particles

The acceleration of an object (in m/s?) is given by the function a(t) = 4 sin(t). The initial velocity of the object is v(0) = - 5 m/s. Round your answers to four decimal places. a) Find an equation v(t) for the object velocity. v(t) = b) Find the object's displacement (in meters) from time 0 to time 3. meters c) Find the total distance traveled by the object from time 0 to time 3. meters

I throw a ball straight up in the air. It travels straight up 2 meters and then straight back down where I catch it at the same height it was released from. The distance the ball has traveled is meters. The displacement of the ball is meters. (use the proper number of sig figs in your answer given the provided information).

There are flies that are flying with a constant altitude of 5 km, that has a velocity of 42km/h. At time t=0 the fly passes directly above a radar station, where t is measured in hours.  a) how fast is the distance between the fly and the radar station changing after ten minutes? provide units and 2 decimal places.  b) how fast is the distance between the bird and the radar station changing at time t=0; when the fly is directly above the radar station? Would it be reasonable, explain?

A car is traveling on a straight, level road under wintry conditions. Seeing a patch of ice ahead of her, the driver of the car slams on her brakes and skids on dry pavement for 70 m, decelerating at 6.0 m/s2. Then she hits the icy patch and skids again. The car takes a duration of 85.0 s to come to rest during the second skid. If her initial speed was 50 m/s, what was the magnitude of the deceleration on the ice during the second skid. 1. Which of the following kinematic equations would you use to determine the velocity of the car after skidding on the dry pavement for 70 m? 2. Determine the velocity of the car after skidding on the dry pavement for 70 m. 3. Which of the following kinematic equations would you use to determine the deceleration of the car after skidding to a stop on the icy patch?   4. Determine the magnitude of the deceleration of the car after skidding to a stop on the icy patch.

The motion of a particle is defined by the relation x = (1/3)t3 – 3t2 + 8t + 2 where x is the distance in meters and is the time in seconds. What is the time when the velocity is zero?