A good workout. You overindulged in a delicious dessert, so you plan to work off the extra calories at the gym. To accomplish this, you decide to do a series of arm raises while holding a 5.0 kg weight in one hand. The distance from your elbow to the weight is 35 cm, and in each arm raise you start with your arm horizontal and pivot it until it is vertical. Assume that the weight of your arm is small enough compared with the weight you are lifting that you can ignore it. As is typical, your muscles are 20% efficient in converting the food energy into mechanical energy, with the rest going into heat. If your dessert contained 350 food calories, how many arm raises must you do to work off these calories? Is it realistic to do them all in one session?
A good workout. You overindulged in a delicious dessert, so you plan to work off the extra calories at the gym. To accomplish this, you decide to do a series of arm raises while holding a 5.0 kg weight in one hand. The distance from your elbow to the weight is 35 cm, and in each arm raise you start with your arm horizontal and pivot it until it is vertical. Assume that the weight of your arm is small enough compared with the weight you are lifting that you can ignore it. As is typical, your muscles are 20% efficient in converting the food energy into mechanical energy, with the rest going into heat. If your dessert contained 350 food calories, how many arm raises must you do to work off these calories? Is it realistic to do them all in one session?
A good workout. You overindulged in a delicious dessert, so you plan to work off the extra calories at the gym. To accomplish this, you decide to do a series of arm raises while holding a 5.0 kg weight in one hand. The distance from your elbow to the weight is 35 cm, and in each arm raise you start with your arm horizontal and pivot it until it is vertical. Assume that the weight of your arm is small enough compared with the weight you are lifting that you can ignore it. As is typical, your muscles are 20% efficient in converting the food energy into mechanical energy, with the rest going into heat. If your dessert contained 350 food calories, how many arm raises must you do to work off these calories? Is it realistic to do them all in one session?
A 20 kg dog stands on a 40 kg platform that is supported by two ropes. One rope is attached to the right edge of the platform and the other is attached 50 cm from the left edge of the platform. The dog sits 50 cm from the right edge of the platform. A 5.0 kg cat jumps up, but is wary of the dog abs stays all the way on the left edge. The platform is 2.0 m long. What is the tension in each rope?
The slope of the 5.0 KN force F is specified as shown in the figure. Express F as a vector in terms of the unit vectors i and j.
Assume a = 13, b = 6.
Answer: F = (
F
b
i+
j) KN
A frustrated farmer is trying to move a large rock from his land. The stone has a mass of 9.00×102 kg. By using a piece of board as a lever and a fulcrum the farmer will have a better chance of moving the rock. The farmer places the fulcrum 0.266 m from the rock so that the edge of the board is located directly under the center of the weight of the rock. The farmer can exert a maximum force of 632.0 N. Calculate the minimum total length of board needed to move the stone?
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