The speed if a bullet of mass 20g is 216km/hr what is its kinetic energy in joules
To find the kinetic energy of the bullet, we can use the formula:
Kinetic energy (KE) = (1/2) * mass * velocity^2
First, we need to convert the mass of the bullet from grams to kilograms. Since there are 1000 grams in a kilogram, the mass of the bullet is:
20g = 20/1000 = 0.02 kg
Next, we need to convert the velocity of the bullet from kilometers per hour (km/hr) to meters per second (m/s). Since there are 1000 meters in a kilometer and 3600 seconds in an hour, we can convert the velocity as follows:
216 km/hr = (216 * 1000) / 3600 = 60 m/s
Now, we can substitute the values into the formula to find the kinetic energy:
KE = (1/2) * 0.02 kg * (60 m/s)^2
Calculating the value:
KE = (1/2) * 0.02 kg * 3600 m^2/s^2
KE = 0.01 kg * 3600 m^2/s^2
KE = 36 J
Therefore, the kinetic energy of the bullet is 36 joules.
To calculate the kinetic energy of the bullet, we need to know its mass and velocity. Given that the mass of the bullet is 20g, which is equivalent to 0.02 kg, and its velocity is 216 km/hr, we can follow these steps to find the kinetic energy:
Step 1: Convert the velocity from kilometers per hour to meters per second.
- 1 km/h = 1000 m/3600 s (since there are 1000 meters in a kilometer and 3600 seconds in an hour)
- So, 216 km/h = (216 × 1000) m/3600 s = 60000 m/3600 s = 50/3 m/s
Step 2: Plug the mass and velocity into the kinetic energy formula:
- Kinetic Energy (KE) = 1/2 × mass × velocity^2
- KE = 1/2 × 0.02 kg × (50/3 m/s)^2
- KE = 1/2 × 0.02 kg × (2500/9) m^2/s^2
- KE = 0.01 kg × (2500/9) m^2/s^2
- KE = (0.01 × 2500)/9 kg × m^2/s^2
- KE = 25/9 kg × m^2/s^2
Therefore, the kinetic energy of the bullet is 25/9 joules, or approximately 2.778 joules.
m = 0.020 kg
v = 216 km/hr ( 1 hr/3600 s)(1000 meters /km) = 60 meters/s
Ke = (1/2)(0.020)(60)^2 Joules