What is the speed of an 800-kg car whose KE is 250 kJ?
Use the formula KE = (1/2) M V^2
Rearrange it to solve for V. You'll need to take a square root along the way.
75 mph
To find the speed of the car, we can rearrange the formula for kinetic energy and solve for velocity.
The formula for kinetic energy is KE = (1/2) M V^2, where KE is the kinetic energy, M is the mass of the object, and V is the velocity.
Given that the mass (M) of the car is 800 kg and the kinetic energy (KE) is 250 kJ, we can substitute these values into the formula:
250 kJ = (1/2) * 800 kg * V^2
Now we can solve for V.
First, let's simplify the equation:
250 kJ = 400 kg * V^2
Next, divide both sides of the equation by 400 kg:
250 kJ / 400 kg = V^2
Simplifying further:
0.625 kJ/kg = V^2
To solve for V, take the square root of both sides of the equation:
√(0.625 kJ/kg) = V
Now calculate the square root:
V ≈ 0.791 km/s
So, the speed of the car is approximately 0.791 km/s.
To find the speed of the car, we will first rearrange the formula for kinetic energy (KE) to solve for velocity (V).
The formula for kinetic energy is given by KE = (1/2) M V^2, where KE represents the kinetic energy, M represents the mass of the object, and V represents the velocity.
Rearranging the formula, we have:
KE = (1/2) M V^2
Multiply both sides of the equation by 2 to remove the fraction:
2 * KE = M V^2
Divide both sides of the equation by M to isolate V^2:
(2 * KE) / M = V^2
Now, take the square root of both sides of the equation to solve for V:
√((2 * KE) / M) = V
Substituting the given values into the formula, we have:
√((2 * 250 kJ) / 800 kg) = V
Calculating the expression within the square root gives us:
√(500 kJ / 800 kg) = V
Simplifying the expression further:
√(0.625 kJ/kg) = V
Taking the square root gives us the final answer:
V ≈ 0.791 m/s
Therefore, the speed of the 800-kg car, with a kinetic energy of 250 kJ, is approximately 0.791 m/s.