a jeepney of a mass 1500kg is travelling at a speed of 20m/s (about 70km/h)
a. what is the kinetic energy of the jeepney?
b.suppose the driver suddenly steps on the brakes. if the force is 7500 newtons, what will be the distance traveled by the jeepney before it stops?
a. KE=1/2 m v2
b. Force*distance=1/2 m v^2
ow btw what's the difference between the two formulas?
What is the answer?
(b) Since Kinetic Energy is equal to W, we can use the formula of W to calculate for KE.
KE= W = Fd ----> substitute the values
30,000 J = 7500 N (d) --> derive the formula to isolate the displacement
d = 30,000J / 7500 N
d = 400 m
To calculate the kinetic energy of the jeepney, you can use the formula:
Kinetic Energy (E) = 0.5 * mass * velocity^2
Let's calculate it step by step.
a. First, we need to convert the mass of the jeepney from kilograms to grams as the kinetic energy formula uses metric units:
Mass of the jeepney = 1500 kg
= 1500 * 1000 g
= 1,500,000 g
b. Now, let's calculate the kinetic energy using the formula:
Kinetic Energy (E) = 0.5 * mass * velocity^2
= 0.5 * 1,500,000 g * (20 m/s)^2
Let's calculate this further:
E = 0.5 * 1,500,000 g * 400 m^2/s^2
To simplify this equation:
E = 300 g * 400 m^2/s^2
= 120,000 g m^2/s^2
Hence, the kinetic energy of the jeepney is 120,000 g m^2/s^2.
Moving on to the next question:
b. To find the distance traveled by the jeepney before it stops, we can use the formula:
Force (F) = mass * acceleration
Rearranging the equation to find acceleration:
Acceleration (a) = Force (F) / mass
Given:
Force (F) = 7500 N
Mass of the jeepney = 1500 kg
a = 7500 N / 1500 kg
Now we can find the acceleration:
a = 5 m/s^2
To find the distance (d), we can use the following formula:
d = (initial velocity)^2 / (2 * acceleration)
Given:
Initial velocity (u) = 20 m/s
Acceleration (a) = 5 m/s^2
d = (20 m/s)^2 / (2 * 5 m/s^2)
Let's calculate it further:
d = 400 m^2/s^2 / 10 m/s^2
= 40 m
Therefore, the jeepney will travel a distance of 40 meters before it stops when the driver applied a force of 7500 Newtons on the brakes.