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Flashcards in Static Equilibrium Deck (11):
1

Static equilibrium is the physics of keeping objects still by applying forces to them. On which of Newton's laws does static equilibrium rely most heavily on?

a. Newton's First Law
b. Newton's Second Law
c. Newton's Third Law
d. Newton's Law of Gravitation

a. Newton's First Law

2

Which of the following is TRUE?

a. A force applied in line with the centre of mass will always cause a rotational motion.
b. A force applied through the pivot point may cause rotational motion.
c. A force applied that is not in line with the pivot point may cause rotational motion.

c. A force applied that is not in line with the pivot point may cause rotational motion.

3

When is the torque the greatest from a person on a bicycle pressing straight down on the pedals as they move the bike forward? (given the 12 o'clock position will be at the top)

a. At the 3 o'clock position when the pedal is closest to the front.
b. At the 4:30 o'clock position when the pedals are angled at 45°
c. At the 6 o'clock position when the pedal is at the bottom point there will be some torque.

a. At the 3 o'clock position when the pedal is closest to the front.

4

A meter stick of negligible mass has a 1.00 kg mass attached at the 0.0 cm mark and a 2.00 kg mass attached to the 100.0 cm mark. Determine the centre of mass in this system.

a. At the 50.0 cm mark
b. At the 20.0 cm mark
c. At the 33.3 cm mark
d. At the 80.0 cm mark
e. At the 66.6 cm mark

e. At the 66.6 cm mark

5

Given the details in the diagram below, what is the torque caused by the applying force (F)? Round your answer to one significant figure.

a. 2000 Nm
b. -7 Nm
c. 20 Nm
d. 1000 Nm
e. 3 Nm

c. 20 Nm

6

Two masses are in static equilibrium on a rod of negligible mass. What is the torque from the unknown mass, which is hanging at some unknown distance from the support string, while a 10.00 kg mass is hanging 0.200 m away from the support string on the other side.
(let clockwise torque be "+")

a. + 49.0 Nm
b. + 19.6 Nm
c. -49.0 Nm
d. -19.6 Nm
e. Not enough information

b. + 19.6 Nm

7

Given the unknown mass in situation in #6 above is actually 15.0 kg, and the two masses remain in static equilibrium on a rod of negligible mass, determine the force of tension in the support string.

a. 49.0 N
b. 98.00 N
c. 25.0 N
d. 245 N
e. Not enough information

d. 245 N

8

Important: the force should act on a hinged object perpendicular to object.

question 9

9

A large adult mass 150 kg, is balancing a much smaller child on a huge 10 m long homogenous wooden teeter-totter. The adult is sitting at a distance of 1m to the right of the fulcrum, and the child's mass is 50 kg. See Diagram below (question 10) How far from the fulcrum would the child have to be?

a. 3 m
b. 5 m
c. 1 m
d. 2 m
e. it totally depends on the mass of the teeter-totter

a. 3 m

10

Given the scenario below (question 11), where a clerk has climbed up a ladder angled at 45°, assuming the wall is perfectly smooth, how would the force on the ladder from the wall (Fw) compare with the force on the ladder from the friction with the ground (Ff)?

a. Fw < Ff
b. Fw = Ff
c. Fw > Ff

b. Fw = Ff

11

A door is pushed on by two forces, a smaller force at the door knob AND a larger force nearer the hinge as shown. The door does not move. see diagram (question 12)

the force exerted on the door by the hinge...
a. is zero
b. points up (along +y)
c. points down (along -y)
d. point lower right
e. points upper right

d. point lower right