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Questions in physics

[Open]1. I drop a penny from the top of the tower at the front of Fort Collins High School and it takes 1.85 seconds to hit the ground. Calculate the velocity in m/s after 1.10 seconds of freefall. Calculate the velocity at impact in mi/hr.

[Open]Engineers who design battery-operated devices such as cell phones and MP3 players try to make them as efficient as possible. An engineer tests a cell phone and finds that the batteries supply 10,000 J of energy to produce 5,500 J of output energy in the form of sound and light for the screen. How efficient is the phone?

[Open]Solve the word problem. The formula \( d = rt \) gives the distance traveled in time \( t \) at rate \( r \). A bicyclist rides at a constant rate of 15 miles per hour. How many miles will he travel in 3.5 hours? A. 4.3 miles B. 18.5 miles C. 23.3 miles D. 52.5 miles

[Open]How would a person's mass be affected by traveling to Saturn, and why?

[Open]Explain the law of conservation of energy in your own words.

[Open]What happens when hot air meets cold air?

[Open]A cheetah can run from 0 to 70 mph in 2.2 seconds. What is its speed in m/s?

[Open]It takes 56.6 joules of energy to raise the temperature of 150 milliliters of water from 5 degrees Celsius to 95 degrees Celsius. If you use an electric water heater that is 60% efficient, how many kilojoules of energy will the heater actually use by the time the water reaches its final temperature?

[Open]A 3 kg chunk of putty moving at a speed of 5 m/s collides with and sticks to a 5 kg bowling ball that is initially at rest. What is their final velocity? Please explain. I am really confused. I know you have to use the conservation of momentum equation: \[ v_f = \frac{m_1 \cdot v_1}{m_1 + m_2} \] where: - \( m_1 \) is the mass of the putty, - \( v_1 \) is the velocity of the putty, - \( m_2 \) is the mass of the bowling ball, - \( v_f \) is the final velocity after collision. Please help!

[Open]Determine the amount of potential energy of a 5-newton book that is moved to three different shelves on a bookcase. The height of each shelf is 1.0 meter, 1.5 meters, and 2.0 meters.