An auto weighing 3000 newtons has a forward drive force of 1000 newtons. Air resistance on the car is 100 newtons, and road resistance is 100 newtons. The auto moves along a straight level road. The force due to gravity acting on the auto is
A) 800 newtons upward.
B) 4200 newtons downward.
C) 3000 newtons upward.
D) zero.
E) 3000 newtons downward.
E
You might also like to view...
Lack of knowledge of the phenomenon called ______________ led Lord Kelvin to an incorrect estimate of the age of Earth
Fill in the blank(s) with correct word
A 1.20-kg ball is hanging on the end of a rope. The rope makes an angle 25.0° from the vertical when a 15.0 m/s horizontal wind blows. If the wind's force on the rope is negligible, what is the drag force on the ball?
A) 32.3 N B) 24.1 N C) 3.68 N D) 5.49 N E) 11.8 N
Measuring the amount of deuterium in the universe allows us to set a limit on
A) the density of ordinary (baryonic) matter the universe. B) the total amount of mass in the universe. C) the acceleration of the universe. D) the current age of the universe.
Solar radiation at 600 W/m2 is absorbed by a black roof inclined at 30°C as shown. If the underside of the roof is well insulated, estimate the maximum roof temperature in Tinf= 20°C air.
GIVEN
• Inclined roof, well insulated on the underside
• Incline angle (?) = 30 degrees
• Air temperature = 20°C
• Solar radiation absorbed (qs) = 600 W/m2
FIND
• The maximum roof temperature
ASSUMPTIONS
• The roof behaves as a black body (? = 1.0)
• The sky behaves as a black body at 0 K
SKETCH
PROPERTIES AND CONSTANTS
The Stephan-Boltzmann constant (?) = 5.67 × 10–8 W/(m2 K4).