A is not true. Venus is one of the brightest objects in the evening sky. It you see it, you will notice it does not blink as the stars do.
B is not true. Venus has NO moons. The Earth has one.
D is not true. Venus is the big surprise of the solar system. It has no magnetic field associated with it. As far as I know, that is unique.
C is the major oddity. Earth rotates once on its axis in 24 hours. Venus takes 243 days to rotate on its axis just one time. The length of a Venetian year is 225 days, so it takes a little over their year to make 1 rotation (compared to our once in 24 hours).
According to the work-energy theorem, the change in the kinetic energy of the combined mass of the child and the sled, is equal to the total work done on the object by external forces.
The external forces capable to do work on the combination of child +sled, are the friction force (opposing to the displacement), and the component of the weight parallel to the slide.
As this last work is just equal to the change in the gravitational potential energy (with opposite sign) , we can write the following equation:
ΔK, is the change in kinetic energy, as follows:
ΔU, is the change in the gravitational potential energy.
If we choose as our zero reference level, the bottom of the slope, the change in gravitational potential energy will be as follows:
Finally, the work done for non-conservative forces, is the work done by the friction force, along the slope, as follows:
Replacing (2), (3), and (4) in (1), simplifying common terms, and rearranging, we have:
Replacing by the givens and the knowns, we can solve for sin θ, as follows: ⇒ θ = sin⁻¹ (0.236) = 13.7º
The magnetic force exerted by a field E to a charge q is given by F=Eq. In this case, F=4.30*10^4*(6.80mu C). 1mu C=10^-6C, so F=4.30*6.80=10^-2=0.29N. The direction is in the x direction, the direction that the field is applied because the charge is positive.