P G7 Turning Effect of Force [PDF]

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Physics Weekly Worksheet G7 S1 – Turning Effect of Force Name: ____________________________ ________________________



Date:



Multiple-Choice Qustions 1. A driver's foot presses on a pedal in a car with a force of 20 N as shown in the diagram. With what force is the spring pulled? A. 2.5 N B. 100 N C. 160 N D. 800 N



2. The diagram shows a uniform beam pivoted at its centre. Forces of 3 N and 4 N act in the directions shown. What is the size and position of the upward force, which will prevent the beam from turning? Size position A. 1 N X B. 1 N Y C. 7 N X D. 7 N Y



3. A door requires a minimum moment of 32.5 Nm in order to open it. What is the minimum distance of the handle from the hinges, if the door is to be pulled open with a force at the handle not greater than 50 N? A. 0.33 m B. 0.65 m C. 0.77 m D. 1.54 m



4. A pivoted uniform bar is in equilibrium under the action of the forces shown. What is the magnitude of the force F? A. 2 N B. 4 N C. 8 N D. 14 N



5. A uniform beam is pivoted at its midpoint. An object is placed on the beam as shown. Which force will rebalance the system?



A. B. C. D.



20 20 50 50



N N N N



acting acting acting acting



downwards, 40 cm to the right of the midpoint upwards, 40 cm to the right of the midpoint downward, 10 cm to the right of the midpoint upward, 10 cm to the left of the midpoint



6. The uniform beam of weight 30 N and length 4 m is hinged at end A, as in the next figure. Which is the force F, in N, which must be applied vertically upwards at a distance of 1 m from end B so that the beam is horizontal? A. 60N B. 50N C. 40N D. 30N



Essay Questions 1. A light beam is supported at its centre and two forces of 5 newtons and 10 newtons act on it



a) If the beam balances, at what distance from the centre must the 10 newton force act? b) What upward force is exerted by the support on the beam?