Physics Test - 9

A uniform ladder rest in limiting equilibrium with its lower end on a rough horizontal plane and its upper end against a smooth vertical wall, ifis an angle of inclination of the ladder to the vertical wall andis the coefficient of friction, then tanis equal to

If each of the two unlike parallel forces P and Q ( P > Q ) acting at a distance d apart be increased by S, then the point of application of the resultant is moved through a distance

With the two forces acting at a point, the maximum effect is obtained when their resultant is 4N. If they act at right angles, then their resultant is 3N. Then the forces are

If a body is in equilibrium under the action of three co-planar forces, then;

ABC is a triangle, forces P, Q, R act along the lines OA, OB and OC and are in equilibrium. If O is in the centre ofABC, then

If the resultant of two forces P and Q acting at an angle  `α` is R, inclined at an angle `θ` with P, then cos θ =

A cart of 100 kg is free to move on smooth rails and a block of 20 kg is resting on it. The surface of contact between the cart and the block is smooth. A force of 60 N is applied to the cart. Acceleration of 20 kg block in m/s2 is

The resultant of two forces P N and 3 N is a force of 7 N. If the direction of the 3 N force was reversed, the resultant would be √19 N. The value of P is

Directions: From the statements of Assertion and Reason mark the correct answer from the options:

(a) If both assertion and reason are true and reason is the correct explanation of assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of assertion.

(c) If assertion is true but reason is false.

(d) If both assertion and reason are false

Assertion: A ladder is more apt to slip, when you are high up on it than when you just begin to climb.

Reason: High up on a ladder, the torque is large and on climbing up the torque is small.

An observer moves towards a stationary source of sound with a velocity one-fifth of the velocity of sound. What is the percentage increase in the apparent frequency?

When a sound wave of frequency 300 Hz passes through a medium, the maximum displacement of a particle of the medium is 0.1 cm. The maximum velocity of the particle is equal to

An aircraft executes a horizontal loop at a speed of 720 km h-1with its wings banked at 150. What is radius of loop?

The resistance of a copper wire is 19.5 ohm. Its length is 8 km and diameter is 3 mm. What is the specific resistance of copper?

A circuit consists of five identical conductors as shown in figure. The two similar conductors are added as indicated by dotted lines.

The ratio of resistances before and after addition will be:

In an LR circuit of 3 mH inductance and 4 resistance, an emf E = 4 cos 1000 t volt is applied. The current amplitude is