Answer:
B. South
Explanation:
An electric field can be defined as the amount of electric force per unit charge. The direction of the electric field can be determined by the motion of a positive test charge under the electric force.
The direction of electric field is radially outward for a positive charge and radially inward for a negative charge. Thus, for the electric field points toward SOUTH at a position directly south of a positive charge.
Answer:
Explanation:
This does not violate Newton's 1st law because the net force would still be 0 in order to produce uniform motion (aka constant velocity). The other forces acting on the vehicles is air resistance which is non-zero. So we need car internal force to counter balance this force, which require extra gas for the car.
<span>The first thing to do here is to figure out how many joules of energy would be produced by your lightbulb in one hour.
As you can see, the conversion factor to use here is
#"1 W" = "1 J"/"1 s"#
This is basically a reminder of the fact that the watt, a unit of power, is defined as an energy of one joule delivered in one second.
Since one hour is known to have #60# minutes, i.e. #60 xx "60 s"#, you will have
#60 xx 60 color(red)(cancel(color(black)("s"))) * "140 J"/(1color(red)(cancel(color(black)("s")))) = "504000 J" = "504 kJ"#
Your next step here will be to use the enthalpy of vaporization of water to figure out how many grams of water would be evaporated by that much heat.
#DeltaH_"vap" = "44.66 kJ mol"^(-1)#
Convert this to kilojoules per gram by using water's molar mass
#44.66 "kJ"/color(red)(cancel(color(black)("mol"))) * (1color(red)(cancel(color(black)("mole H"_2"O"))))/("18.015 g") = "2.479 kJ g"^(-1)#
This means that the mass of water that can be evaporated by #"504 kJ"# of heat will be
#504color(red)(cancel(color(black)("kJ"))) * ("1 g H"_2"O")/(2.497color(red)(cancel(color(black)("kJ")))) = "201.8 g"#
Now, assuming that the sweat is pure water, you can approximate its density to be equal to #"1.0 g mL"^(-1)#. This means that the volume of water that can be evaporated will be
#201.8 color(red)(cancel(color(black)("g"))) * "1 mL"/(1.0color(red)(cancel(color(black)("g")))) = color(green)(bar(ul(|color(white)(a/a)color(black)(2.0 * 10^2 "mL")color(white)(a/a)|)))#
The answer is rounded to two</span>
Answer:
161.86 N
Explanation:
mass of box m= 55.0 kg
weight of the box, mg= 55×9.81
g here is acceleration due to gravity =9.81 m/sec^2
coefficient of friction between the box and the surface μ= 0.3
the friction force F_s= μmg= 0.3×55×9.81
=161.86 N
to move the ball horizontal force required is 161.86 N
