Which of the following is an example of convection?

the rays of the Sun warming the earth

a hot oven warming the air around it

a hot object transferring heat to a cooler one

hot air rising and cooler air falling

When finding net force, why must you know the directions of the forces acting on an object? Give two reasons.

Two vectors, of magnitudes 20 mm and 50 mm, are added together. Which one of the following is a possible value for the magnitude of the resultant? a. 10 mm b. 20 mm c. 40 mm d. 80 mm

When is a wire size an electrical hazard?

Select the correct answer. A body travels 10 meters during the first 5 seconds of its travel, and it travels a total of 30 meters over the first 10 seconds of its travel. What Its average speed during the time from t = 5 seconds to t = 10 seconds? A.

What is the mass and weight of a 10kg object on the moon where the force of gravity is 1/6-th that of the earth's?

The magnetic flux through each turn of a 110-turn coil is given by ΦB = 9.75 ✕ 10-3 sin (ωt), where ω is the angular speed of the coil and ΦB is in webers. At one instant, the coil is observed to be rotating at a rate of 8.70 ✕ 102 rev/min.

A comet has a period of 324 years; in other words, it orbits the Sun in 324 years. Most likely, this comet came from ... (Hint: 324 years define a long period comet) A. Somewhere outside the solar system B. Oort's cloud C. The ecliptic plane D.

4. A pendulum oscillates 12 times in 4 seconds. a. What is the frequency of the pendulum's oscillations? b. What is the period of the pendulum's oscillations?

How many protons and electrons are present in a vanadium atom?

A dog runs 27 m in 3 s. what is the dogs average speed. a 9 m/s b 24 m/s c 30 m/s d 81 m/s