Question

An object of mass 8.0 kg moves with a uniform speed of 25 m/s. Calculate the force that must be applied to this object so that it comes to a halt in 10 seconds.

A rock falls under a gravitational force of 16.3 N on the moon. Given that the acceleration due to gravity on the moon is one-sixth of that on the Earth, find the mass of the rock.

A. 40 N; 98.4 kg
B. 200 N; 100 kg
C. 250 N; 160 kg
D. 100 N; 16.3 kg

Answer 1

The force required to bring the object to a halt is 200 N. The mass of the rock is 160 kg.

Step-by-step explanation:

To calculate the force required to bring the object to a halt, we can use the formula:

Force = (mass x final velocity - mass x initial velocity) / time

Plugging in the values, Force = (8.0 kg x 0 - 8.0 kg x 25 m/s) / 10 s = -200 N

The negative sign indicates that the force is in the opposite direction of the initial motion.

Therefore, the force that must be applied to this object to bring it to a halt in 10 seconds is 200 N.

Given that the gravitational force on the moon is 16.3 N and the acceleration due to gravity on the moon is one-sixth of that on Earth, we can find the mass of the rock:

mass = gravitational force / (acceleration due to gravity on moon)

Plugging in the values, mass = 16.3 N / (1/6 x 9.8 m/s²) = 160 kg

Therefore, the mass of the rock is 160 kg.