A girl runs up a stairway that is 6m high with a 500g book, her mass is 70kg. Take g=10m/s2 calculate (a) weight of the book (b) weight of the girl (c) the total work done by the girl when she reaches the top
g is not 10m/s^2 anywhere on this Earth. I have never understood why teachers do that...do they think students are stupid and can only use whole numbers (500g, 70kg, 10m/s^2)?
weightofbook= mass*g
weight of girl= mass*g
work= (massbook+massgirl)g*6 joules
To find the weight of an object, you need to multiply its mass by the acceleration due to gravity (g).
(a) Weight of the book:
Given that the mass of the book is 500g (0.5kg) and acceleration due to gravity is 10m/s^2, you can calculate the weight of the book using the formula:
Weight = mass * acceleration due to gravity
Weight of the book = 0.5kg * 10m/s^2
Weight of the book = 5 N
(b) Weight of the girl:
Given that the mass of the girl is 70kg and acceleration due to gravity is 10m/s^2, you can use the same formula to calculate her weight:
Weight of the girl = 70kg * 10m/s^2
Weight of the girl = 700 N
(c) Total work done by the girl:
Work is calculated by multiplying the force applied by the displacement covered. In this case, the force applied is equal to the weight of the girl, and the displacement is equal to the height of the stairway (6m).
Total work done by the girl = Force * Distance
Total work done by the girl = Weight of the girl * Distance
Total work done by the girl = 700N * 6m
Total work done by the girl = 4200 Joules
Therefore, (a) the weight of the book is 5 N, (b) the weight of the girl is 700 N, and (c) the total work done by the girl when she reaches the top is 4200 Joules.