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Effitol840

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Alright I'm having trouble with 3 of my 10 problems I have for homework. I do calculations and everything but I always seem to come up with the wrong answer. If anyone can help me out that wold be great. The problems are as follows:

1. A certain cable car is San Francisco can stop in 10 s when traveling at maximum speed. On one occasion, the driver sees a dog a distance d m in front of the car and slams on the brakes instantly. The car reaches the dog 8.6 s later, and the dog jumps off the track just in time. If the car travels 4.5 m beyond the position of the dog before coming to a stop, how far was the car from the dog?

2. Suppose a small child rolls off a bed that is 0.44 m above the floor. If the floor is hardwood, the child's head is brought to rest in approximately 1.9 mm. If the floor is carpeted, this stopping distance is increased to about 1.0 cm. Calculate the magnitude and duration of the deceleration in both cases, to determine the risk of injury. Assume that the child remains horizontal during the fall to the floor. Note that a more complicated fall could result in a head velocity greater or less than the speed you calculate.

3. A hard rubber ball, released at chest height (1.50 m), falls to the pavement and bounces back to nearly the same height. When it is in contact with the pavement, the lower side of the ball is temporarily flattened. Before this dent in the ball pops out, suppose that its maximum depth is 1.10 centimeter. What is the maximum upward acceleration of the ball?

The following equations are supposed to be helpful with all of these problems:

[tex]v[/tex]=velocity [tex]v_{0}[/tex]=initial velocity [tex]\Delta x[/tex]=change in distance [tex]a[/tex]=accelertion

[tex]t[/tex]=time

[tex]vt=\Delta x[/tex]

[tex]v=v_{0}+at[/tex]

[tex]v^2=v_{0}^2+2a\Delta x[/tex]

[tex]\Delta x=v_{0}t+\frac{1}{2}at^2[/tex]

If anyone can help me with how to get started with these the correct way that would be great. Thanks.

1. A certain cable car is San Francisco can stop in 10 s when traveling at maximum speed. On one occasion, the driver sees a dog a distance d m in front of the car and slams on the brakes instantly. The car reaches the dog 8.6 s later, and the dog jumps off the track just in time. If the car travels 4.5 m beyond the position of the dog before coming to a stop, how far was the car from the dog?

2. Suppose a small child rolls off a bed that is 0.44 m above the floor. If the floor is hardwood, the child's head is brought to rest in approximately 1.9 mm. If the floor is carpeted, this stopping distance is increased to about 1.0 cm. Calculate the magnitude and duration of the deceleration in both cases, to determine the risk of injury. Assume that the child remains horizontal during the fall to the floor. Note that a more complicated fall could result in a head velocity greater or less than the speed you calculate.

3. A hard rubber ball, released at chest height (1.50 m), falls to the pavement and bounces back to nearly the same height. When it is in contact with the pavement, the lower side of the ball is temporarily flattened. Before this dent in the ball pops out, suppose that its maximum depth is 1.10 centimeter. What is the maximum upward acceleration of the ball?

The following equations are supposed to be helpful with all of these problems:

[tex]v[/tex]=velocity [tex]v_{0}[/tex]=initial velocity [tex]\Delta x[/tex]=change in distance [tex]a[/tex]=accelertion

[tex]t[/tex]=time

[tex]vt=\Delta x[/tex]

[tex]v=v_{0}+at[/tex]

[tex]v^2=v_{0}^2+2a\Delta x[/tex]

[tex]\Delta x=v_{0}t+\frac{1}{2}at^2[/tex]

If anyone can help me with how to get started with these the correct way that would be great. Thanks.

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