297

Physics Force & Laws Of Motion Level: High School

A horizontal shove of at least 200-N is required to start moving a 800-N crate initially at rest on a horizontal floor . Find the coefficient of static friction .



296

Physics Force & Laws Of Motion Level: High School

A brick slides on a horizontal surface. Which of the following will increase the frictional force on it ?

A. Putting a second brick on top.

B. Decreasing the surface area of contact.

C. Increasing the surface area of contact.

D. Decreasing the mass of the brick

E. None of the above.

Putting a second brick on top. ( This will increase the normal reaction and hence the frictional force )



295

Physics Force & Laws Of Motion Level: High School

Two blocks with masses m and M are pushed along a horizontal frictionless surface by a horizontal applied force F as shown in the figure at “click here” . The magnitude of the force that either of these blocks exerts on the other is

a) mFl(m+M)

b) mFlM

c) mFl(M-m)

d) MFl(M+m)

e) MFlm




294

Physics Force & Laws Of Motion Level: High School

Three blocks (A,B,C) each having mass M , are connected by string as shown in the figure at “click here”. Block C is pulled to the right by a force F that causes the entire system to accelerate . Neglecting friction. Find the net force acting on block B .



293

Physics Force & Laws Of Motion Level: High School

Two blocks weighing 250 N and 350 N respectively , are connected by a string that passes over a massless pulley as shown in the figure at “click here” Calculate the tension in the string .



292

Physics Force & Laws Of Motion Level: High School

The “reaction” force does not cancel the “action” force because :

a) the action force is greater than the reaction force .

b) they act on different bodies .

c) they are in the same direction .

d) the reaction force exists only after the action force is removed .

e) the reaction force is greater than the action force .

Ans: They act on different bodies .



291

Physics Force & Laws Of Motion Level: High School

A 1.5 N ball is thrown at an angle of 30 degree above the horizontal with an initial speed of 12 m/s. At its highest point , the net force on the ball is

a) 9.8 N , 30 degree below horizontal

b) zero

c) 9.8 N , up

d) 9.8N , down

e) 1.5N , down

Ans: 1.5 N down .



290

Physics Force & Laws Of Motion Level: High School

A 25 kg chair is pushed across a frictionless horizontal floor with a force of 20N , directed 20 degree below the horizontal . The acceleration of the chair is :

a) 0.27 m/s^2

b) 0.75 m/s^2

c) 0.80 m/s^2

d) 170 m/s^2

e) 470 m/s^2




289

Physics Force & Laws Of Motion Level: High School

The block shown moves with constant velocity on a horizontal surface . Two of the forces acting on the block are shown a frictional force exerted by the surface is the only other horizontal force acting on the block . The friction force is

a) 0

b) 2N. leftward

c) 2N. rightward

d) slightly more than 2N, leftward

e) slightly less than 2N, leftward.




288

Physics Force & Laws Of Motion Level: High School

A heavy wooden block is dragged by a force F along a rough steel plate , as shown in the figure at “click here”. The magnitude of the applied force F is the same for both cases . The normal force in (ii) , as compared with the normal force in (i) is :

a) the same

b) greater

c) less

d) less for some angles of the incline and greater for others

e) less or greater, depending on the magnitude of the applied force F




287

Physics Force & Laws Of Motion Level: High School

Two forces one with a magnitude of 3N and other with a magnitude of 5N, are applied to an object. For which orientations of the forces shown in the diagram is the magnitude of the acceleration of the object the least ?

a) I

b) II

c) III

d) IV

e) V




285

Physics Force & Laws Of Motion Level: High School

Mass deffers from weight in that :

a) all objects have weight but some lack mass

b) weight is force and mass is not

c) the mass of an object is always more than its weight

d) mass can only be expressed in the metric system.

e) there is no difference

weight is a force and mass is not .



284

Physics Force & Laws Of Motion Level: High School

The inertia of a body tends to cause the body to

a) speed up

b) slow down

c) resist any change in motion

d) fall toward the earth

e) decelerate due to friction

resist any change in its motion .



283

Physics Force & Laws Of Motion Level: High School

The term “mass” refers to the same physical concept as:

a) weight

b) inertia

c) force

d) acceleration

e) volume

(b) inertia



281

Physics Force & Laws Of Motion Level: High School

The standard 1-kg mass is attached to a compressed spring and the spring is released . If the mass initially has an acceleration of 5.6 m/s^2 , the force of the spring has a magnitude of :

2.8N

b) 5.6N

c) 11.2N

d) 0

e) E. an undetermined amount.

m = 1 Kg, a = 56 m/s^2 F = ma = 1 X 5.6 = 5.6 N

Displaying 631-645 of 709 results.