Accceleration/Velocity questions

[ariol]

Okay, I am beyond completely lost. I know you have to use certain equations to figure these out but other then that I'm completely clueless how to do them. If you could help that would be great. This is worth five bonus points on my grade if I can answer all these corectly.
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Your can is traveling 23.0 m/s when you see the car in front of you slam on the breaks and stop. If you do the same but it takes you 0.8 sec to react because your texting on your cell-phone and you slow down at a rate of 7.6 m/s^2 to avoid hitting that car, how far will your car go before it stops? Show all work. (Round to the tenths)
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A football player jumped up and picked off a pass then ran it back for a touchdown. If it took him 6 sec to score and his velocity was 8.6 m/s when he crossed the goal line, how many yards did he return the interception for? Show all work. (Round off meters to yards)
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Graph a velocity-time line (solid) and the acceleration-time line (dashed) of a ball being rolled up an incline by a push of a person's hand, changing direction and rolled back down and stopped by the catch of the person's hand.
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On a gold green you putt a golf ball up a slope at 2.0 m/s. Assuming up is positive, if the ball slows at a rate of .72 m/s^2 how fast will it be traveling after 2 sec? Show all work.
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A punter on a football team kicks a punt 17 meters high into the air. How fast is it traveling when the return man catches the ball? Show all work.
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A feather is placed in a 2 m long vacuum tube that has all the air removed from it. If you flip the tube upside-down how long will it take for the feather to fall to the bottom of the tube? Show all work.
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The value of gravity on the moon is one sixth what it is on earth. If a ball was rolled down a slope, would it take the ball more, less, or equal time to toll to the bottom as compared to on earth? Show all work.

 

[physics girl phd]

Welcome to the forums!

Unfortunately, you first need to show us what equations you think you'll need to use, and how you'll apply them in each case... we'll then help if you seem stuck.

 

[thomate1]

I am happy to assist you with these acceleration/velocity questions. It is important to remember that acceleration is the rate of change of velocity over time, and velocity is the speed of an object in a specific direction. In order to solve these types of problems, we use equations such as distance = velocity x time and final velocity = initial velocity + acceleration x time.

For the first question, we have the initial velocity of the car as 23.0 m/s and an acceleration of -7.6 m/s^2 (since the car is slowing down). We also have a reaction time of 0.8 seconds. Using the equation final velocity = initial velocity + acceleration x time, we can find the final velocity of the car before it stops. -7.6 m/s^2 x 0.8 s = -6.08 m/s. This means the final velocity of the car is 23.0 m/s - 6.08 m/s = 16.92 m/s. Now, we can use the equation distance = velocity x time to find the distance traveled by the car. 16.92 m/s x 0.8 s = 13.536 m. Therefore, the car will travel 13.536 meters before it stops.

For the second question, we are given the velocity of 8.6 m/s and the time of 6 seconds. We can use the equation distance = velocity x time to find the distance traveled by the football player. 8.6 m/s x 6 s = 51.6 m. Since we are asked to round off meters to yards, the football player returned the interception for 56.5 yards (51.6 m converted to yards).

For the third question, we can create a velocity-time graph and an acceleration-time graph to represent the motion of the ball being rolled up an incline and back down. The velocity-time graph would show a positive slope as the ball is being pushed up the incline, then a negative slope as it rolls back down. The acceleration-time graph would show a flat line during the time the ball is being pushed, then a steep negative slope as the ball rolls back down and is caught by the person's hand.

For the fourth question, we are given the initial velocity of 2.0 m/s and an acceleration of -0.72 m/s^2 (since the ball is slowing down). We also