Gravitational potential energy and kinetic energy
7 flashcards to master this topic
Derive the formula for the change in gravitational potential energy (ΔEp) in a uniform gravitational field using W = Fs.
Work done (W) equals force (F) times distance (s). In this case, the force is weight (mg) and the distance is the change in height (Δh). Therefore, ΔEp = W = Fs = mgΔh.
State the formula for the change in gravitational potential energy (ΔEp) in a uniform gravitational field.
ΔEp = mgΔh, where 'm' is mass, 'g' is the acceleration due to gravity, and 'Δh' is the change in height. This formula applies near the Earth's surface where 'g' is approximately constant.
A 2 kg mass is lifted 1.5 m vertically. Calculate the change in its gravitational potential energy.
Using ΔEp = mgΔh, where m = 2 kg, g = 9.81 m/s², and Δh = 1.5 m, we get ΔEp = (2 kg)(9.81 m/s²)(1.5 m) = 29.43 J.
Derive the formula for kinetic energy (Ek) using equations of motion.
Starting with v² = u² + 2as, rearrange to get s = (v² - u²)/2a. Work done, W = Fs = mas = ma(v² - u²)/2a = (1/2)mv² - (1/2)mu². If starting from rest (u=0), then Ek = (1/2)mv².
State the formula for kinetic energy (Ek).
Ek = (1/2)mv², where 'm' is the mass of the object and 'v' is its velocity. Kinetic energy is the energy an object possesses due to its motion.
Calculate the kinetic energy of a 5 kg object moving at 4 m/s.
Using Ek = (1/2)mv², where m = 5 kg and v = 4 m/s, we get Ek = (1/2)(5 kg)(4 m/s)² = 40 J.
Describe the relationship between kinetic energy and velocity.
Kinetic energy is directly proportional to the square of the velocity. This means that if the velocity doubles, the kinetic energy quadruples.
Ready to test yourself?
Practice with MCQ questions to check your understanding of Gravitational potential energy and kinetic energy.
Take QuizStudy Mode
Rate each card Hard, Okay, or Easy after flipping.