Question

. A constant force of 125 N acts on an object
at rest. After traveling a distance of 8m, the
speed of the object is 10 m/s. The mass of
the object is:
(A) 1.25 kg
(B) 2.5 kg
(C) 5 kg
(D) 10 kg​

Answer 1

Given Information,

• Force Applied (F) = 125 N
• Initial Velocity (u) = 0 m/s
• Final Velocity (v) = 10 m/s
• Displacement (s) = 8m

From Work Energy Theorem,

Net Work Done = Change in Kinetic Energy

Here, initial KE is inconsiquential as the object was at rest initially.

$\longrightarrow$ F × s = 1/2mv²

$\longrightarrow$ 125 × 8 × 2 = 100m

$\longrightarrow$ 100m = 250 × 8

$\longrightarrow$ 100m = 2000

$\longrightarrow$ m = 20Kg

Mass of the object is 20Kg.

Answer 2

Answer:

20KG

Explanation:

Force - 125N (F = ma) where "m" is mass and "a" is acceleration.

$Acceleration = ?$

$Initial Velocity (u) = 0 (given at rest)$

$Final Velocity (v) = 10m/s$

$Distance = 8m$

According to the 3rd Equation of Motion,

$v^{2}$$- u^2$$= 2as$

Where "a" is acceleration and "s" is distance.

$So,$

$100 - 0 = 16a$

$a = 100/16 = 6.25 m/s^2$

$Acceleration * Mass = Force$

$6.25m/s^2 * Mass = 125N$

$Mass = 125 / 6.25$

$Mass = 20kg$

THE REQUIRED ANSWER IS 20KG.