Other Physics Answers

A particle whose mass is 3 kg moves in the xy plane with velocity along the

line y=5.3 m.

(a) Find the angular momentum about the origin when the particle is at (12 m, 5.3 m).

(b) A force is applied to the particle. Find the torque about the origin due to

this force as the particle passes through the point (12 m, 5.3 m).

A door with width 1.2 m and mass M = 10 kg is hinged on one side so that it can rotate

freely. A bullet is fired into the center of the door. The bullet has mass 25 g and a speed of

300 m/s. What is the angular velocity of the door with respect to the hinge just after the

bullets embeds itself in the door?

The uniform bar of length L 40 N and is subjected to four forces shown. Find the

magnitude, location and direction of a fifth force F needed to keep the bar in equilibrium.

A propeller with three blades of mass 12 kg each, length of 1.25 m each are 120 degrees relative to each other. If a torque 3000 N.m acts on this, what is the moment of inertia of the propeller,? How long will it take to reach an angular velocity of 2000 rad/s starting from rest?

How much potential energy does a car gain if a crane lifts the car with a mass of 1,500kg and 20m straight up?

Consider an automobile moving at v mph that skids d feet after its brakes lock. Calculate how far it would skid if it was moving at 2v and the brakes were locked.

The driver of a 2.0 × 103 kg red car traveling on the highway at 45m/s slams on

his brakes to avoid striking a second yellow car in front of him, which had come

to rest because of blocking ahead as shown in above Fig. After the brakes are

applied, a constant friction force of 7.5 × 103 N acts on the car. Ignore air

resistance.

(a) Determine the least distance should the brakes be applied to avoid a

collision with the other vehicle?

(b) If the distance between the vehicles is initially only 40.0 m, at what speed

would the collision occur?

(c) Write your conclusive observations on the result obtained from this

numerical. I.e. the importance of Physics in daily life.

Solution

3

3

:

2.0 10

45 /

7.5 10

Given data in this Question

mass of the car is kg

velocity of the car is u m s

final velocity v

Friction force is kg

 

 

 

 

A non-uniform zinc rod 60cm weighs 32N is balanced at the 45cm mark. A load of 2N is hung on the zinc rod at the 25cm mark. Where should a second knife-edge be placed to balance the rod horizontally

Explain how pure metal and a semi conductor can be distinguished through the effect of temperature on their electrical resistance

A car is driving at constant speed down the road.  The mass of the car is 1350 kg and the coefficient of rolling friction is 0.18?  How much engine force is needed to keep the car moving? [Hint:  Draw a free body diagram]