Question

If someone falls at a rate of 2 kg/s, how long in seconds will it Take someone with a mass of 119 lb To fall Off a hill?

Answer 1

Answer:

27 s.

Explanation:

We have to do the calculations with the right units, so let's convert from 119 lb to kg. Remember that 1 lb equals 0.454 kg. Based on this information we can state a rule of three and the conversion will look like this:

$119\text{ lb}\cdot\frac{0.454\text{ kg}}{1\text{ lb}}=54.0\text{ kg.}$

Now, we have to do a dimensional analysis to obtain the answer. We want to find the time that this person falls off a hill, and time is in seconds, so we have to 'cancel' the mass in kg to obtain seconds and this would be a multiplication. A 2 kg mass falls in one second, this multiplied by the mass of the person is:

$54.0\text{ kg}\cdot\frac{1\text{ s}}{2\text{ kg}}=27\text{ s.}$

The answer would be 27 s.