Question 59
Using a model arm to investigate how the biceps muscle works
You are going to investigate how the size of the force produced by the biceps muscle differs, if it is attached at different positions on the radius.
You will need: model arm, like the one in the diagram; some masses on a hanger; forcemeter.
Topic 3.4 showed that the arm acts like a lever. In this investigation, you are going to try attaching the ‘biceps muscle’ at different points along the ‘radius’, to find out the force needed to lift a weight.
Set up your model arm like this.
Method
1 Read through the instructions given in the method. Then construct a chart to fill in your results.
2 Put some masses on the hanger. Start with just one or two masses. (Make sure you record these masses in your results chart.)
3 Attach the forcemeter to hook 1. Pull gently and steadily vertically upwards until the ‘radius’ makes a right angle with the ‘humerus’. Record the reading on the forcemeter as you keep the radius in this position.
4 Now attach the forcemeter to hook 2, and repeat.
5 Repeat again, with the forcemeter attached to hook 3 and then hook 4.
6 Put some more masses on the hanger. Repeat steps 3 to 5.
You are going to investigate how the size of the force produced by the biceps muscle differs, if it is attached at different positions on the radius.
You will need: model arm, like the one in the diagram; some masses on a hanger; forcemeter.
Topic 3.4 showed that the arm acts like a lever. In this investigation, you are going to try attaching the ‘biceps muscle’ at different points along the ‘radius’, to find out the force needed to lift a weight.
Set up your model arm like this.
Method
1 Read through the instructions given in the method. Then construct a chart to fill in your results.
2 Put some masses on the hanger. Start with just one or two masses. (Make sure you record these masses in your results chart.)
3 Attach the forcemeter to hook 1. Pull gently and steadily vertically upwards until the ‘radius’ makes a right angle with the ‘humerus’. Record the reading on the forcemeter as you keep the radius in this position.
4 Now attach the forcemeter to hook 2, and repeat.
5 Repeat again, with the forcemeter attached to hook 3 and then hook 4.
6 Put some more masses on the hanger. Repeat steps 3 to 5.
