Answer:
She is going at 30.4 m/s at the top of the 35-meter hill.
Explanation:
We can find the velocity of the skier by energy conservation:
On the top of the hill 1 (h₁), she has only potential energy since she starts from rest. Now, on the top of the hill 2 (h₂), she has potential energy and kinetic energy.
(1)
Where:
m: is the mass of the skier
h₁: is the height 1 = 82 m
h₂: is the height 2 = 35 m
g: is the acceleration due to gravity = 9.81 m/s²
v₂: is the speed of the skier at the top of h₂ =?
Now, by solving equation (1) for v₂ we have:
Therefore, she is going at 30.4 m/s at the top of the 35-meter hill.
I hope it helps you!
Answer:
Explanation:
From the given information:
The initial PE 
= m×g×h
= 5 kg × 9.81 m/s² × 10 m
= 490.5 J
The change in Potential energy P.E of the box is:
ΔP.E = 
ΔP.E = 0 -
ΔP.E = 
If we take a look at conservation of total energy for determining the change in the internal energy of the box;
this can be re-written as:
Here, K.E = 0
Also, 70% goes into raising the internal energy for the box;
Thus,
ΔU = 343.35 J
Thus, the magnitude of the increase is = 343.35 J
Answer:
5880lb-ft of work is done
Explanation:
The length of the heavy rope is given as 60ft and the weight per length is 0.7lb/ft.
Therefore, the total weight of the heavy rope is
60×0.7 =42lb.
The work done in pulling the heavy rope to the top of the building is w = Fd.
Where
F is force is measured in pounds;42lb
d is distance through which the heavy rope is to be pulled measured in feet; 140ft
w= 42lb×140ft= 5880lb-ft
Answer:
friction reduces the efficiency of machines, thus we must reduce the friction force that is acting upon it.
Answer:
1. Urea, (d)Fertilizer
2. Combines, (c) Harvesting and threshing
3. Silos, (b) Storage of grains
4. Seed drills, (a) Sowing seeds
5. Irrigation, (f) Sprinklers
6. Tilling, (e) Preparation of soil
Explanation:
1) Urea is a widely used and important fertilizer in the agricultural industry
2) The combine harvester combines three categories of harvesting grain drops such as threshing reaping and winnowing
3) Silos are used to store grains
4) A seed drill is a seed planting mechanism for burying seeds to a particular depth during seed planting
5) Irrigation is the application of required volume of water to plants
6) Tilling is the digging, turning, and staring operations meant to prepare the soil.
