Other Physics Answers

A pendulum is formed from a small rock with mass of 0.10 kg that is fastened to a massless string

with length 0.750 m. It is swinging so as to make a maximum angle of 45.0 with the vertical. Air

resistance is negligible. What is the tension in the string as it passes through the vertical?

What is the capacitance of a parallel plate capacitor with metal plates, each of area 1.00 m2, separated by 1.00 mm?

The magnetic flux through a coil of wire containing two loops changes at a constant rate from -58 Wb to 38 Wb in 0.34 s. What is the emf induced in the coil?

When the blender is empty and running at high speed, how much time is required for a blade to turn by 90 degrees

10. A pulley system operated with an electric motor consumes 5.0 kJ of energy as it does 3.2 kJ of work in raising an object. The efficiency of this technology is:

(a) 64% (b) 84%

(c) 119% (d) 156%

8. Consider an object falling from a height of 300 m. If we ignore air resistance, its total energy:

(a) increases during the fall.

(b) decreases during the fall.

(c) remains constant during the fall.

(d) is zero at the start of the fall.

7. In which of the following is gravitational potential energy being transformed into kinetic energy?

(a) A car accelerating on a level road.

(b) A raindrop falling freely through the air.

(c) Water turning an electric turbine.

(d) A stone thrown up into the air.

6. If the mass of an object is quadrupled and the speed decreased by a factor of three, by what factor does the kinetic energy change?

(a) 4/3 (b) 16/3

(c) 4/9 (d) 16/9

9. A 6.0 kg object (at rest) is released from a height of 80 m. If air resistance is negligible and g = 9.8 N/kg, the kinetic energy of the mass when it is 20 m above the ground is:

(a) 4.7 × 103 J (b) 3.5 × 103 J

(c) 2.4 × 103 J (d) 1.2 × 103 J

Cody car accelerates from 0m/s to 45m/s northward in 15 seconds. What is the acceleration of the car?