Laws of Motion

• -αv²

This question has Statement 1 and Statement 2 . Of the four choices given after the Statements, choose the one that best describes the two Statements.

Statement 1: If you push on a cart being pulled by a horse so that it does not move, the cart pushes you back with an equal and opposite force.

Statement 2: The cart does not move because the force described in statement 1 cancel each other.

JEE Main 2012 (26 May Online)

• Statement 1 is true, Statement 2 is true, Statement 2 is the correct explanation of Statement 1.

• Statement 1 is false, Statement 2 is true.

• Statement 1 is true, Statement 2 is false.

• Statement 1 is true, Statment 2 is not the correct explanation of Statement 1.

Sand is being dropped on a conveyer belt at the rate of 2 kg per second. The force necessary to keep the belt moving with a constant speed of 3 m/s will be

JEE Main 2012 (19 May Online)

• 12N

• 6N

• Zero

• 18N

A block of weight W rests on a horizontal floor with coefficient of static friction μ. It is desired to make the block move by applying minimum amount of force. The angle θ from the horizontal at which the force should be applied and magnitude of the force F are respectively.

JEE Main 2012 (19 May Online)

Two point masses of mass m₁=fM and m₂=(1−f)M (f<1) are in outer space (far from gravitational influence of other objects) at a distance R from each other. They move in circular orbits about their centre of mass with angular velocities ω₁ for m₁ and ω₂ for m₂. In that case

JEE Main 2012 (19 May Online)

• ω_{1 =} ω₂ and independent of f

• fω₁ = (1-f)ω₂

• ω_{1 =} ω₂ and depend on f

An insect crawls up a hemispherical surface very slowly. The coefficient of friction between the insect and the surface is 1/3. If the line joining the centre of the hemispherical surface to the insect makes an angle α with the vertical, the maximum possible value of α so that the insect does not slip is given by

JEE Main 2012 (12 May Online)

• cotα = 3

• secα = 3

• cosecα = 3

• cosα = 3

A car of mass 1000 kg is moving at a speed of 30 m/s. Brakes are applied to bring the car to rest. If the net retarding force is 5000 N, the car comes to stop after travelling d m in t s. Then

JEE Main 2012 (07 May Online)

• d = 150 , t = 5

• d = 120 , t = 8

• d = 180, t = 6

• d = 90, t = 6

An engine pumps water continuously through a hose. Water leaves the hose with velocity v and m is mass per unit length of the water jet. If this jet hits a surface and came to rest instantaneously, the force on the surface is

JEE Main 2012 (07 May Online)

• mv³

• mv²

A particle of mass m is at rest at the origin at time t=0. It is subjected to a force F(t)=F0e−bt in the x direction. Its speed v(t) is depicted by which of the following curves?

JEE Main 2012 (offline)

• 
• 
• 
• 

This question has statement 1 and statement 2. Of the four choices given after the statements, choose the one that best describes the two statements.

If two springs S1 and S2 of force constants k1 and k2, respectively, are stretched by the same force, it is found that more work is done on spring S₁ than on spring S₂.

Statement 1 : If stretched by the same amount, work done on S₁, will be more than that on S₂ Statement 2: k₁ < K₂

_{JEE Main 2012 (offline)}

• Statement 1 is false, Statement 2 is true

• Statement 1 is true, Statement 2 is false

• Statment 1 is true, Statement 2 is the correct explanation for Statement 1

• Statement 1 is true, Statement 2 is true, Statement 2 is not the correct explanation for Statement 1.