Chapter 4-5 (moment, force and pressure)

In the diagram above, two masses, one with mass m, the other with mass M = 2m are resting on a uniform plank of length L that pivots at its midpoint. If the mass m is at the far end of the plank, how far away from the pivot should the mass M be to balance the plank in a horizontal position shown?

• L/2
• L/3
• L/4
• L/6

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NGSS.MS-PS2-4

NGSS.MS-PS2-2

When an object is experiencing a net moment

• it is in dynamic equilibrium.
• it is in static equilibrium.
• it is rotating.
• it is translating.

A 15-kg child is sitting on a playground teeter-totter, 1.5 m from the pivot. What is the magnitude of the minimum force, applied 0.30 m on the other side of the pivot, that is needed to make the child lift off the ground?

• 66 N
• 740 N
• 23 N
• 44 N

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NGSS.MS-PS2-4

NGSS.MS-PS2-2

The point through which the whole weight of the body acts is called

• Inertial Point

• Center of gravity

• Centriod

• Central point

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NGSS.MS-PS2-4

Where will be the centre of gravity of a uniform rod lies ?

• At its end

• At its middle point

• At its centre of its cross sectional area

• Depends upon its material

A simple method to find centre of gravity of a body is usage of

• stop watch

• plumbline

• pendulum

• gauge

What is one way you might increase the stability of an object?

• Lower the center of gravity

• Raise the center of gravity

• Increase the height of the object

• Shorten the base of the object

Tags

NGSS.MS-ETS1-2

NGSS.MS-ETS1-1

Why is the car on the right more stable?

• Its centre of mass is higher

• it has a wider base

• it has more height

• all of the above

Tags

NGSS.MS-PS2-4

NGSS.MS-ETS1-2

NGSS.MS-ETS1-1

What is the center of mass ?

• it is a single point at which the object can balance.

• The mass is distributed equally around it.

• the center of gravity of the object

• All of the above

Tags

NGSS.MS-PS2-4

A block with center of mass X touches the ground at point P. In which diagram will the block topple?

• 
• 
• 
• 

Tags

NGSS.MS-PS2-4