Exam 3: Mechanical Objects, Part 1

A friend of your joins a weight loss group. Unfortunately, they try to control the readings on the scales by having you weigh yourself on either level ground or with the scale on a slight slope. How will the two weights obtained by these two different methods compare?

You are extremely bored during the long summer months when school is out of session, so you decide to attach a graphing calculator to a rubber band and repeatedly bounce it up and down vertically. When the rubber band is at its maximum stretch away from your hand

You are playing with your younger cousins and find yourself on all fours, with your hands and feet on four bathroom scales on the level ground. You took a "Physics in Everyday Life" course so you can make a reasonable guess that the reading on each scale is obtained by

In a soccer game, someone has kicked the ball so that it is heading right toward your face. You want to slow the ball down with your arm. To execute your plan most effectively you should

A popular playground toy is a flexible seat that has automobile springs attached to it for a little bounce. When a 200 N child sits on the toy, it compresses 5 mm downward. What is the ride's spring constant?

Suppose a soap box car is coasting on a track (no motor; no brake), moving from left to right, and part of the track is shown below. Friction /air resistance is present and the car comes to a stop at point E. -Please identify points of maximum and minimum total energy, if any.

A person is swinging a tin can around in a vertical circle at a constant speed. Please identify the points, if any, of -maximum/ minimum value (magnitude) of centripetal acceleration

A person is swinging a tin can around in a vertical circle at a constant speed. Please identify the points, if any, of -maximum/ minimum total mechanical energy

Why do balls that deform bounce poorly?

Why do elastic balls bounce so well?

A bathroom scale reads

You are on an airplane waiting to take off for a summer trip. Having just come from your physics final, you decide to measure the acceleration of the plane during takeoff by tying your graphing calculator to a string and suspending it. Your new device will do a great job of measuring the plane's constant acceleration during takeoff because, as the plane accelerates your calculator will

When a baseball player hits a ball, the bat can respond by

Suppose your instructor staggers into class after an all-weekend pocket protector seminar and workshop. With the best of intentions, she tells you in going through an example for the class that an object in motion is clearly not in equilibrium. Please comment on the scientific validity of your instructor's statement.

You decide to go out to a baseball game Friday night and notice that the best hits are from the players that follow through with their swings. Why is it important to follow through when hitting or kicking a ball?

You have heard the tried and true phrase "it is like running in to a brick wall". Now it is time to dig a little deeper and modify the phrase. Assume you are in a car driving and come in contact with this proverbial brick wall. Your car can do three things after the strike: it can go through, come to stop or bounce back. Assuming the car is in contact with the wall for the same amount of time for all three cases, select the option which will be the most dangerous to you from a force point of view and briefly discuss why the assumption of equal times has to be made.

A bat moving at 90 km/h strikes an oncoming ball moving at 110 km/h. If the batter follows through so that the speed of the bat doesn't change during the hit and the coefficient of restitution of the ball is 0.6, what speed does the batted ball have after it has been struck?

You are at a swimming pool and notice that different persons make the diving board bend by different amounts when they stand still on it. Assuming the board to behave like a spring (perfectly elastic) please discuss how you could secretly determine the weight of everybody that uses the board if you known the weight of one person that uses it.

You go through a loop in a roller coaster at constant speed. Where is your apparent weight a minimum?

You are swinging a tin can around your head in a perfectly horizontal circle of radius 4 m. (This is really not possible but we're saying it almost happens.) If the speed of the can is 4 m/s and its mass is 2 kg, what inward force is required to keep the can moving in the circle?