Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
Please help me I'm about to fail physics ):?
A 70.0 kg sailor climbs a 28.3 m rope ladder at an angle of 45.0° with the mast. How much work did he do? Hint: The answer is NOT 1,400 J
The forklift exerts a 300.0 N force on the box and moves it 15.0 m forward level into the air. How much work does the forklift do? Hint: The answer is NOT 500J
A sailboat moves north for a distance of 10.00 km when blown by a wind from the exact south with a force of 5.00 × 104 N. How much work was done by the wind? Hint: The answer is NOT 3.54 x 105 J.
3 Answers
- Randy PLv 77 years ago
Work is force times distance in the direction of the force.
First one: The force is mg, the vertical distance is 28.3 cos(45) m. So the work is 70 kg * 9.8 m/s^2 * 28.3 cos(45)
Second one: That would be 300 N times the vertical distance, which was not given. There is 0 work done in moving the box horizontally because that distance is perpendicular to the force. Did the picture show a vertical distance?
Third one: F * d
- 7 years ago
1). Work W = (70.0 kg)(9.8 m/s^2)(28.3 m )(sin 45) = 13727 Joules ~ 14000 J
If your teacher says this isn't corrrect, he/she is wrong.
2). 0 Joules. The motion is horizontal , so no work is done against gravity.
3). Work = ( 5 x 10^4 N) ( 10^4 m) = 5 x 10^8 J
Source(s): PhD in physics, and I teach physics. - SteveLv 77 years ago
W = m*g*L*sinΘ = 13728 J
No idea what 'level into the air' means
W = F*d = 10E3*5E4 = 50E7 J
