Physics Answers

A large punch bowl holds 3.50 kg of lemonade (which is essentially water) at 25.0 ° C. A 5.70x10 2-kg ice cube at -12.0 °C is placed in the lemonade. What is the final temperature of the system? Ignore any heat exchange with the bowl or the surroundings. What is the amount of ice (if any) remaining

A mass of 0.30 kg attached to a vertical spring, stretches the spring by 10 cm. Find

(a) the spring constant k.

(b) Work done by gravity and the spring force.

(c) the maximum restoring force.

(d) What is the change in gravitational potential energy?

A pillow is dropped on the earth from the height of 3.40 meters. The acceleration of gravity on the earth is -9.8m/s2. Determine the time for the feather to fall to the surfec of the earth

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.

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).

What color code corresponds to a resistance of 234x105±10% with a temperature coefficient of resistance equal to 25x10-6/Co?

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?