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# 10 Physics questions: Acceleration, speed, air resistance, density, temperature, work

1. You push with a 50-N horizontal force on a 10 kg mass resting on a horizontal surface against a horizontal friction force of 20N. What is the acceleration?

2. A railroad diesel engine weighs six times as much as a freight car. If the diesel engine coasts a 7km per hour into a freight car that is intially at rest, how fast do the tow coast after they couple together?

3. A car moving at 20km.h skids 10m with locked brakes. How far will the car skid with locked brakes at 120km/h?

4. A cannonball shot with an intial velocity of 150m/s at an angle of 45 degrees follows a parabolic path and hits a balloon at the top of its trajectory. Ignoring air resistance, how fast is the cannonball going when it hits the balloon?

5. A vacationer floats lazily in the ocean with 93% of his body below the surface. The density of ocean water is 1,025 kg/m^3. What is the vacationer's average density?

6. What will be the final temperature of 100g of 25 degree C water when 100 g of 45 degree C iron nails are submerge in it. (The specific heat of iron is 0.12 cal/g. The specific heat of water is 1.00 cal/g.)

7. An electric iron connected to a 100-V source draws 10A of current. How much heat (in joules) does it generate in a minute?

8. A weight suspended from a spring is seen to bob up and down over a distance of 40 centimeters twice each second. What is frequency? Its period? Its amplitude? Include units.

9. Balance the chemical equation and be sure to show your work!

___ CH4 + ____O2 &#8594; ____CO2 + _____H2O

10. How many grams of ozone, O3 (48 amu), can be produced from 96 grams of oxygen, O2(32amu), in the following reaction - show all work!

3 O2 &#8594; 2 O3

#### Solution Summary

With excellent explanation and calculations, the problems are solved.

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