Questions from Modern Physics

Q: Adult cheetahs, the fastest of the great cats, have a

Adult cheetahs, the fastest of the great cats, have a mass of about 70 kg and have been clocked to run at up to 72 mi/h 132 m/s2. (a) How many joules of kinetic energy does such a swift cheetah have?...

Q: (a) In the Bohr model of the atom, the

(a) In the Bohr model of the atom, the ground-state electron in hydrogen has an orbital speed of 2190 km/s. What is its kinetic energy? (Consult Appendix F.) (b) If you drop a 1.0-kg weight (about 2 l...

Q: About 50,000 years ago, a meteor crashed into the

About 50,000 years ago, a meteor crashed into the earth near present-day Flagstaff, Arizona. Measurements from 2005 estimate that this meteor had a mass of about 1.4 × 108 kg (around 150,000 tons) and...

Q: Using a cable with a tension of 1350 N, a tow

Using a cable with a tension of 1350 N, a tow truck pulls a car 5.00 km along a horizontal roadway. (a) How much work does the cable do on the car if it pulls horizontally? If it pulls at 35.0° above...

Q: A 4.80-kg watermelon is dropped from rest from

A 4.80-kg watermelon is dropped from rest from the roof of an 18.0-m-tall building and feels no appreciable air resistance. (a) Calculate the work done by gravity on the watermelon during its displace...

Q: Use the work–energy theorem to solve each of these problems

Use the work–energy theorem to solve each of these problems. You can use Newton’s laws to check your answers. Neglect air resistance in all cases. (a) A branch falls from the top of a 95.0-m-tall redw...

Q: Use the work–energy theorem to solve each of these problems

Use the work–energy theorem to solve each of these problems. You can use Newton’s laws to check your answers. (a) A skier moving at 5.00 m>s encounters a long, rough horizontal patch of snow having a...

Q: You are a member of an Alpine Rescue Team. You must

You are a member of an Alpine Rescue Team. You must project a box of supplies up an incline of constant slope angle a so that it reaches a stranded skier who is a vertical distance h above the bottom...

Q: You throw a 3.00-N rock vertically into the

You throw a 3.00-N rock vertically into the air from ground level. You observe that when it is 15.0 m above the ground, it is traveling at 25.0 m/s upward. Use the work–energy theorem to find (a) the...

Q: A sled with mass 12.00 kg moves in a straight

A sled with mass 12.00 kg moves in a straight line on a frictionless, horizontal surface. At one point in its path, its speed is 4.00 m/s; after it has traveled 2.50 m beyond this point, its speed is...