Kinetic, Potential and Mechanical energy

Kinetic energy can be calculated using the formula: ​ (a)  

where m is ​ (b)   unit in ​ (c)  

and v is ​ (d)   unit in ​ (e)  

• mass
• kg
• velocity
• m/s
• mv
• weight
• km/h
• volume

Gravitational potential energy can be calculated using the formula:​ (a)  

where m is​ (b)   unit in ​ (c)  

g is ​ (d)   unit in m/s²

h is ​ (e)   unit in meter

• mass
• gravitational acceleration
• height
• kg
• m + g + h
• mass + speed + distance
• force = mass x acceleration

​ (a)   is the sum of kinetic energy and ​ (b)  

• mechanical energy
• gravitational potential energy
• elastic potential energy
• chemical energy
• magnetic potential energy

Based on the law of conservation of energy, in closed system mechanical energy of system is ​ (a)   . It means that initial and final mechanical energy is ​ (b)  

• constant
• equal
• decreasing
• unequal
• fluctuating
• increasing

A 100 kg roller coaster car is move 40 m/s. calculate kinetic energy of the car​ (a)  

• 80 kJ
• 200 kJ
• 50 kJ
• 120 kJ

• 19.6 kJ
• 5.0 kJ
• 50 kJ
• 200 kJ

A 100 kg roller coaster car is at rest near the top of a 20 m high track. It is released and travels to the bottom of the track. Determine the kinetic energy of the car at the bottom of the track. Assume gravitational acceleration is 9.8 m/s2 and there is no energy lost ​ (a)  

• 19.6 kJ
• 5.0 kJ
• 50 kJ
• 100 kJ

Most roller coasters begin at ground level. The ride usually takes thrill seekers slowly up to the tallest point in the ride. Let’s take a look at this particular roller coaster ride. The elevations (i.e. heights above ground level) at the various points are given in brackets. For simplicity, we will assume that there is negligible air resistance and friction between the car and tracks, unless otherwise stated. We will also assume that a fully loaded car weighs about 10,000 N, and that gravitational field strength g = 10 N kg–1. Determine the change in gravitational potential energy of the fully loaded car as it moves from A to B.

​ (a)  

• 500 kJ
• 100 kJ
• 1,000 kJ
• 50 kJ

A typical roller coaster has several peaks and troughs. In this particular roller coaster, there are three peaks (A, C and E) and three troughs (B, D and F), with heights given in the diagram below.

State which position have/has the greatest amount of gravitational potential energy​ (a)  

State which position have/has the greatest amount of kinetic energy ​ (b)  

• A
• F
• B
• C
• D
• E

A pendulum bob of mass 20 g is released from rest at A. It swings from A to C and back to A via B, as shown in the diagram.

Determine G.P.E at A​ ​ (a)  

Determine Kinetic Energy at C ​ (b)  

Determine velocity of bob pendulum at B ​ (c)   ​

• 10 mJ
• 1 m/s
• 0 J
• 5 mJ
• 2 m/s
• 1 J