Answer:
4180 N
Explanation:
In order to keep the truck balanced and stationary, the force of friction on the truck must be equal to the component of the weight of the truck acting parallel to the slope.
The component of the weight of the truck acting parallel to the slope is:
where
m = 3500 kg is the mass of the truck
g = 9.8 m/s^2 is the acceleration of gravity
is the angle of the slope
Therefore, the force of friction must be equal to
Answer:
Explanation:
The work done on the object at rest is all converted into kinetic energy, so we can write
Or, re-arranging for v,
where
v is the final speed of the object
W is the work done
m is the object's mass
If the work done on the object is doubled, we have W' = 2W. Substituting into the previous formula, we can find the new final speed of the object:
So, the new speed of the object is .
Explanation:
As you can see in the picture, we want the swimmer to go on a straight line, so the speed of the water must be equal to the speed of the swimmer along the x-axis. We also know the value of v, so we can calculate the of the cosine of the angle (alpha) between Vx and V. Thanks to the fundamental relation of gioniometry (cos^2(x) + sin^2(x) = 1) we can find the sine of alpha and calculate Vy. With Vy we can calculate the time that the swimmer will use for reaching the dock: s = Vy * t => t = s/(Vy).
I'll let you do all the calculations, you just have to plug in values.
