Answer:
0.466 (3 sig. fig.)
Explanation:
Frictional force acting on the box = 5.00×10^2xsin25
Normal force acting on the box = 5.00×10^2xcos25
coefficient of friction = 0.466 (3 sig. fig.)
Answer:
Explanation:
a )
hear energy required to melt 1 g of ice = 340 J ,
hear energy required to melt 80 g of ice = 340 x 80 J = 27220 J .
b ) energy gained by the melted ice ( water at O°C ) = m ct
where m is mass of water , s is specific heat and t is rise in temperature
= 80 x 4.2 x ( 8°C - 0°C)
= 2688 J .
c )
energy lost by lime juice = energy gained by ice and water
= 27220 J + 2688 J .
= 29908 J .
d )
Let specific heat required be S
Heat lost by lime juice = M S T
M is mass of lime juice , S is specific heat , T is decrease in temperature
= 320 g x S x ( 29 - 8 )°C
= 6720 S
For equilibrium
Heat lost = heat gained
6720 S = 29908 J
S = 4.45 J /g °C .
Answer:
F = W + ma a> 0
Explanation:
For this exercise let's use Newton's second law
we assume the upward direction as positive
F - W = m a
F = W + ma
F = m (g + a)
In this case they indicate that the speed is less and less as it goes down, therefore the acceleration must be opposite to the speed, that is, the acceleration is upwards, consequently it is positive
We can see that since a> 0 the force F must have greater than the weight of the elevator
<span>In order for
an object to accelerate, a <u>force</u> must be applied. It follows Newton’s second
law of motion where it states that a body at rest remains at rest unless a
force is acted upon it. When you move an object, you are exerting a force onto
it. By exerting a force on the object, you are actually displacing it from its
initial position. You cannot apply force to the object without altering its
position. Keep in mind that when you exert work, you are exerting energy too. </span>
