What is the kinectic energy in joules of a 500kg automobile traveling at 45km/hr?
To find the kinetic energy (KE) of an object, you need two pieces of information: its mass (m) and its velocity (v). The formula for calculating kinetic energy is KE = (1/2)mv^2.
In this case, the mass of the automobile is given as 500 kg, and its velocity is given as 45 km/hr. However, we need to convert the velocity from kilometers per hour to meters per second (m/s) since the SI unit system uses meters and seconds.
To convert km/hr to m/s, we need to multiply the velocity by a conversion factor.
1 kilometer = 1000 meters
1 hour = 3600 seconds
So, the conversion factor is (1000 m / 1 km) / (3600 s / 1 hr) = 1000 / 3600 = 0.2778 m/s.
Now, we can convert the velocity:
Velocity (in m/s) = 45 km/hr * 0.2778 m/s
Velocity (in m/s) = 12.5 m/s (rounded to one decimal place)
Now that we have the mass (m = 500 kg) and the velocity (v = 12.5 m/s), we can calculate the kinetic energy (KE):
KE = (1/2) * m * v^2
KE = (1/2) * 500 kg * (12.5 m/s)^2
KE ≈ 156250 Joules
Therefore, the kinetic energy of a 500kg automobile traveling at 45km/hr is approximately 156,250 Joules.