DPP 1 -Force

1. The moment of couple is mathematically the:

• product of one force and the perpendicular distance between two forces

• product of both forces and the perpendicular distance between them

• product of one force and the perpendicular distance between the point of application of force and turning point.

• None of the above.

A force F acts on a rigid body capable of turning around a fixed point. The moment of force depends upon:

• magnitude of force F

• magnitude of perpendicular distance between the point of action of force and the turning point

• both (a) and (b)

• none of these

The perpendicular distance between the point of application of force and the turning point is 1.75 m, when a force of 80 N acts on a rigid body. Calculate the moment of force.

• 180 Nm

• 140 Nm

• 220 Nm

• 370 Nm

The diagram alongside shows a force F = 5 N acting at point A produces a moment of force of 6 Nm about point O. What is the diameter of the wheel?

• 1.0 m

• 4.6 m

• 2.4 m

• 3.4 m

Study the diagram alongside and calculate the moment of couple.

• 1 Nm

• 6 Nm

• 2 Nm

• 4 Nm

A uniform metre scale is balanced at 20 cm mark, when a weight of 100 gf is suspended from one end. Where must the weight be suspended? Calculate the weight of the metre scale.

• 11.11 gf

• 66.66 gf

• 77.77 gf

• 88.88 gf

A uniform wooden beam, 80 cm long and weighing 250 gf, is supported on a wedge as shown in the figure. Calculate the greatest weight which can be placed on end A without causing the beam to tilt.

• 100 gf

• 375 gf

• 560 gf

• 750 gf

A practice of mass m is executing a uniform circular motion on a path of radius r. If p is the magnitude of its linear momentum, then what is the radial force acting on the particle?

• $\frac{p^2}{mr}$
  
  

• $\frac{r}{p}$

• $\frac{rm}{p^2}$

  
  

• $\frac{p}{m}$

What type of motions are exhibited by a vehicle and its wheels?

• Translatory

• Translatory and rotatory

• Rotatory

• None of these

A see-saw 8 m long is balanced in the middle. Two children of mass 30 kgf and 40 kgf are sitting on the same side of the fulcrum at a distance of 1.5 m and 3.5 m from the fulcrum respectively. Where must a lady weighing 60 kgf sit from the fulcrum, so as to balance the see-saw?

• 2.17 m

• 3.08 m

• 4.15 m

• 6.15 m