has a greater kinetic energy than the other. How is this possible?
A. One object is blue and one object is red.
B. One object has a greater volume than the other object.
C. One object has a greater speed than the other object.
D. One object has a greater density then the other object.
9 answers
The fact that one object has a greater kinetic energy than the other, despite both having equal masses, can be explained by their speeds. Kinetic energy is given by the formula:
\[ KE = \frac{1}{2} m v^2 \]
where \( m \) is the mass and \( v \) is the speed of the object. Since the masses are equal, the kinetic energy will depend primarily on the square of the speed.
Therefore, the correct answer is:
C. One object has a greater speed than the other object.
Kinetic energy is given by the formula:
\[ KE = \frac{1}{2} m v^2 \]
where \( m \) is the mass and \( v \) is the speed of the object. In this case, both the truck and the car are moving at the same speed. However, since the truck has a greater mass than the car, it will have more kinetic energy.
Therefore, the correct response is:
The truck has more kinetic energy because it has a greater mass.
To determine which object has the greatest kinetic energy, we can use the kinetic energy formula:
\[ KE = \frac{1}{2} m v^2 \]
Given that all cars have the same mass of 500 kg, we can compare the kinetic energies by looking solely at the speed (v).
Red car: \[ KE = \frac{1}{2} \times 500 \times (3)^2 = \frac{1}{2} \times 500 \times 9 = 2250 , \text{J} \]
Blue car: \[ KE = \frac{1}{2} \times 500 \times (30)^2 = \frac{1}{2} \times 500 \times 900 = 225000 , \text{J} \]
Green car: \[ KE = \frac{1}{2} \times 500 \times (21)^2 = \frac{1}{2} \times 500 \times 441 = 110250 , \text{J} \]
Yellow car: \[ KE = \frac{1}{2} \times 500 \times (12)^2 = \frac{1}{2} \times 500 \times 144 = 36000 , \text{J} \]
Now comparing the kinetic energies:
The blue car moving at 30 m/s has the greatest kinetic energy.
Therefore, the answer is:
The blue car with a mass of 500 kg moving at 30 m/s.
To determine who has the greater kinetic energy, we need to consider both mass and speed. The kinetic energy (KE) is calculated using the formula:
\[ KE = \frac{1}{2} m v^2 \]
If the wildlife keeper has a significantly greater mass than the rabbit and they are both moving at similar speeds, the kinetic energy of the wildlife keeper will be greater due to the larger mass.
If the rabbit is moving much faster than the wildlife keeper, then the rabbit may have greater kinetic energy despite its smaller mass.
The option stating "Neither one because they are moving at the same speed" does not provide enough information, as it does not consider the masses of the individuals.
In the context of this question, since the wildlife keeper typically has a greater mass compared to a rabbit, we can infer:
The wildlife keeper because they have a greater mass.
However, it's important to note that the actual determination of kinetic energy would depend on both their respective masses and velocities, which are not provided in the question. If specific speeds or additional context were known, it would be clearer. But based on typical scenarios, mass plays a significant role.
Kinetic energy (KE) is given by the formula:
\[ KE = \frac{1}{2} m v^2 \]
where \( m \) is the mass and \( v \) is the speed of the object.
As the skydiver accelerates, his speed increases from 20 m/s to 30 m/s, and then finally to a constant speed of 50 m/s.
Based on this understanding, the correct statement is:
His kinetic energy increased while his speed increases, then it became constant.
