A 70 kg student traveling in a car with a constant velocity has a kinetic energy of 1.4 104 J. What is the speedometer reading of the car in km/h?
Well, if the student is traveling with a constant velocity, it means the car isn't accelerating. So, to find the speedometer reading of the car, we need to use the equation:
Kinetic Energy = (1/2) * mass * velocity^2
Since we're given the kinetic energy (1.4 * 10^4 J) and the mass (70 kg), we can rearrange the equation to solve for the velocity:
velocity = √(2 * Kinetic Energy / mass)
Plugging in the values, we get:
velocity = √(2 * 1.4 * 10^4 J / 70 kg)
Now, let me grab my calculator... *humming the calculator song*
Velocity = 14 m/s
But hold on! You asked for the speedometer reading in km/h, not m/s! Silly me!
Let me convert that for you:
1 m/s = 3.6 km/h
So, multiplying the velocity by 3.6, we get:
Velocity = 50.4 km/h
Voila! The speedometer reading of the car is 50.4 km/h. And remember, no clowning around with speeding! Safety first! 🤡🚗
To find the speedometer reading of the car in km/h, we can use the formula for kinetic energy:
K.E = (1/2)mv^2
Where:
K.E is the kinetic energy (1.4 * 10^4 J)
m is the mass of the student (70 kg)
v is the velocity of the car (unknown)
Rearranging the formula to solve for v:
v^2 = (2 * K.E) / m
Substituting the given values:
v^2 = (2 * 1.4 * 10^4 J) / 70 kg
v^2 = 4 * 10^2 J/kg
Taking the square root of both sides:
v = √(4 * 10^2 m^2/s^2)
Now, we need to convert the velocity from m/s to km/h.
1 m/s = 3.6 km/h
Therefore:
v = √(4 * 10^2) m/s x 3.6 km/h / 1 m/s
v = √(1600) x 3.6 km/h
v = 40 x 3.6 km/h
v = 144 km/h
So, the speedometer reading of the car is 144 km/h.
To find the speedometer reading of the car in km/h, we first need to calculate the speed of the car.
The kinetic energy (KE) of an object can be calculated using the formula:
KE = (1/2)mv^2
Where:
KE = kinetic energy
m = mass
v = velocity
In this case, the kinetic energy is given as 1.4 * 10^4 J (Joules) and the mass is given as 70 kg.
1.4 * 10^4 J = (1/2) * 70 kg * v^2
To find v^2, we can rearrange the equation:
v^2 = (2 * 1.4 * 10^4 J) / 70 kg
v^2 = 400
Taking the square root of both sides to solve for v:
v = √400
v = 20 m/s (meters per second)
To convert meters per second to kilometers per hour, we need to multiply the speed by a conversion factor of 3.6:
v = 20 m/s * 3.6 km/h
v = 72 km/h
Therefore, the speedometer reading of the car would be 72 km/h.