Answer: Thus, the force is directed 72.5° above the horizontal.
Explanation:
The magnitude of the force, F = 15 N
let this force be detected at angle θ from the horizontal, then horizontal component of force is: F cos θ
and vertical component is F sin θ
Horizontal component is given,
F cos θ = 4.5 N
⇒15 N cos θ = 4.5 N
⇒ cos θ = 0.3
⇒ θ = cos⁻¹ 0.3 = 72.5°
Answer:
I HOPE THIS IS CORRECT
Explanation:
Power of water =2 kw=2000w
Mass of water =200kg
difference in temperature ΔT=70−10=60oC
Concept
energy required to heat the water = energy given by water in time t=pt
energy required to increase tempeature of water by 60oC,Q=msΔT
S= specific heat =4200J/kgoC
pt=msΔT
2000×t=200×4200×60
t=25200
or t=25.2×103sec.
The position of the first ball is
while the position of the second ball, thrown with initial velocity , is
The time it takes for the first ball to reach the halfway point satisfies
We want the second ball to reach the same height at the same time, so that
First, we need to fight the weight of the balls instead of their mass. We do this by multiplying their weight it kg by 9.8. This gives us .98 N. To find the potential energy of the rolling ball, we find its kinetic energy. The formula for this is KE=mass*velocity^2*1/2.
Plugging in our numbers, we have Kinetic energy = .1 * 1^2*1/2 which gives us .05 joules.
Now we find the potential energy of the ball on the shelf. For this we do:
Potential energy = .1*9.8*1, and our answer is .98 joules. Clearly, the ball on the shelf has more energy.