PROBLEMS

1.Assuming that the world record for the 100-m dash is about 10 s, how fast are humans capable of running in m/s?Can you change this speed to miles per hour? (There are 1609 m in 1 mi, and 3600 s in 1 h)
22.37 mi/h

2.What is the acceleration of a vehicle that changes its velocity from 100 km/h to a dead stop in 10 s?
You can use the kinematics equation vf-vi=at
a=(vf-vi)/t
*(0-100)/10=10 in units of  km/(hr*s)

3.A ball is thrown straight up with an initial speed of 30 m/s.How high does it go,and how long is it in the air (neglecting air resistance)
High=45.92 meters
Long=3.061 seconds

4.A ball is thrown with enough speed straight up so that it is in the air several seconds.

a.What is the velocity of the  ball when it gets to its highest point?
zero

b.What is its velocity 1 s before it reaches its highest point?
one second before reaching the top,it is moving up at v=10 m/s

c.What is the change in its velocity during this 1 s interval?
dv=9.8 m/s

d.What is its velocity 1 s after it reaches its highest point?
v=9.8 m/s

e.What is the change in velocity during this 1 s interval?
dv=9.8 m/s

f.What is the change in velocity during the 2 s interval?
dv=18.6 m/s

g.What is the acceleration of the ball during any of these time intervals and when it passes through the zero velocity point?
At any point acceleration is a=9.8 m/s/s

5.What is the instantaneous velocity of a freely falling object 10 s after it is released from a position of rest? What is its average velocity during this 10 s interval?How far will it go during this time?
average velocity=49 m/s
i.velocity=98 m/s
distance=490 meters

6.A climber near the summit of a vertical cliff accidentally knocks loose a large rock.She sees it shatter at the bottom of the cliff 8 s later.What was the speed of impact?How far did the rock fall?
Far: 313.92 meters
final speed: 78.4 m/s for 8 seconds

7.A car goes from v=0 to v=50 m/s in 10 s.If you wish to find the distance traveled using the equation d=1/2at2,what value should you use for a?
a=5 m/s2

8.Consider a planet where the acceleration due to gravity is 20 m/s2.How fast and how far will an object at rest freely fall in 1 s?Compared to earth,how much greater and farther are the speed and distance fallen on this planet at given times?
10 m/s2.
20 m/s2

9.Surprisingly,very few athletes can jump more than 2 feet (0.6 m) straight up.Use d=1/2at2 and solve for the time one spends moving upward in a 2-foot vertical jump.Then double it for the "hang time"-the time one's feet are off the ground.
t=0.1625 seconds
hang time=0.403 seconds

10.Calculate the vertical height of Michael Jordan's jump when he attains a hang time of a full 1 s.
4.9meters