A student weighing 300 N climbed a flight of stairs 5.0 m high in 6 s. How much work was done by the student?
a. 1500 J
b. 1800 J
c. 1500 W
d. 1800 W
e. 50 W
a
You might also like to view...
Rotational Kinetic Energy: A solid uniform cylinder is rolling without slipping. What fraction of its kinetic energy is rotational?
A. 1/3 B. 2/3 C. 1/2 D. 1/4 E. 3/4
A star radiates most strongly at 600 nanometers. What is its surface temperature?
A. 7,250 K B. 483 K C. 6,000 K D. 72,500 K E. 4,830 K
What evidence is there that Earth has been struck by large meteorites?
What will be an ideal response?
The handle of a ladle used for pouring molten lead is 30-cm-long. Originally the handle was made of 1.9 x 1.25 cm mild steel bar stock. To reduce the grip temperature, it is proposed to form the handle of tubing 0.15-cm-thick to the same rectangular shape. If the average heat transfer coefficient over the handle surface is 14 W/(m2 K), estimate the reduction of the temperature at the grip in air at 21°C.
GIVEN
FIND
The reduction of the temperature at the grip
ASSUMPTIONS
The lead is at the melting temperature
The handle is made of 1% carbon steel
The ladle is normally in steady state during use
The variation of the thermal conductivity is negligible
One dimensional conduction
Heat transfer from the end of the handle can be neglected
SKETCH
