Question

An object moving with a speed of 67m/s and has a kinetic energy of 500J. What is the mass o the object?​

Answer 1

Speed (v) = 67 m/s

Mass (m) = ??

Kinetic energy = 500J

1/2 mv² = 500J

1/2×m×(67)² = 500

1/2×m×4489 = 500

m = 500×2/4489

Mass = 0.223 kg (approx.)

(The mass has been found in approximation because of the given data)

Answer 2

Given:

• Speed = 67 m/s
• K.E = 500 J

To Find:

• The mass of the object.

Solution:

we know that Kinetic energy, K.E = $\frac{1}{2}mv^2$  → {equation 1}

where "m" is the mass, "v" is the speed.

rearrange equation 1 in such a way that we can find the value of mass and substitute the given values in the same equation. We get,

⇒ m = $\frac{2*K.E}{v^2}$  = $\frac{2*500}{67*67}$

In the above equation first, we multiply the values in the numerator. We get,

⇒ m = 1000/4489 = 0.22276 = 0.2 Kg

In the above formula, division operation is used to get the value of "m".

In the above equation, we can write 0.22276 as 0.2 as we rounded the decimal figures to one significant figure.

∴ The mass of the object = 0.2 Kg.