Answer:
B) The car at point C has less kinetic energy than the car at point B.
Explanation:
We have two types of energy involved in this situation:
- Gravitational potential energy: this is the energy related to the heigth of the car, and it is given by 
, where m is the mass of the car, g is the gravitational acceleration, and h is the heigth of the car. The potential energy is higher when the car is located higher above the ground.
- Kinetic energy: this is the energy due to the motion of the car, and it is given by 
, where m is the mass of the car and v is its speed. The kinetic energy is higher when the speed of the car is higher.
- The law of conservation of energy states that the total mechanical energy of the car (sum of potential energy and kinetic energy: 
) is constant). This implies that when the car is at a higher point, the kinetic energy is less (because U is larger, so K must be smaller), while when the car is at a lower point, the kinetic energy is larger.
- Based on what we have written so far, we can conclude that the correct statement is:
B) The car at point C has less kinetic energy than the car at point B.
Because the car at point C is located at a higher point than point B, so the car at point C has larger potential energy than at point B, which implies that car at point C has less kinetic energy than the car at point B.
The siren will seem to get louder as the ambulence approches, and it will seem to get quieter as the ambulence drives away.
Heat absorbed is given by multiplying the specific heat capacity with the mass of the substance and the change in temperature.
specific heat capacity of iron= 460.5 J/kg/k
therefore, heat = mcФ, where c is heat capacity, m is the mass of iron and Ф is change in temperature. Change in temperature is 14 (20-6), mass in kg (0.057 kg)
=460.5 × 0.057 x 14
= 367.48 joules
Hence, heat absorbed by iron will be 367.48 joules
Answer:
violet
Explanation:
violet has shortest wavelength
Answer:
A 20 Hz sound wave is 75 m long in the water (1500/20 = 75) whereas a 20 Hz sound wave in air is only 17 m long (340/20 = 17) in air. As we descend below the surface of the sea, the speed of sound decreases with decreasing temperature.
