<h3><u>Answer;</u></h3>
a) 5.00 x 10^8 J
<h3><u>Explanation;</u></h3>
The work done to move the sailboat is calculated through the equation;
W = F x d
where F is force and d is the distance.
Substituting the known values from the given above,
W = (5.00 x 10⁴ N)(10 km)(1000 m/ 1km)
= 5.00 x 10⁸ J
Thus, the work done is <u>5.00 x 10⁸Joules</u>
There are mistakes in the question.The correct question is here
A 2.0 kg, 20-cm-diameter turntable rotates at 100 rpm on frictionless bearings. Two 500 g blocks fall from above, hit the turntable simultaneously at opposite ends of a diameter, and stick. What is the turntable’s angular velocity, in rpm, just after this event?
Answer:
w=50 rpm
Explanation:
Given data
The mass turntable M=2kg
Diameter of the turntable d=20 cm=0.2 m
Angular velocity ω=100 rpm= 100×(2π/60) =10.47 rad/s
Two blocks Mass m=500 g=0.5 kg
To find
Turntable angular velocity
Solution
We can find the angular velocity of the turntable as follow
Lets consider turntable to be disk shape and the blocks to be small as compared to turntable

where I is moment of inertia

You can look at magnesium, it can react with oxygen to form oxides. (chemical) it is malleable and a solid at room temperature. (physical)
to measure its density, the mass and volume can be worked out and from this density too. look up the equation, it is quite easy :)
physical changes -- it can be melted, and oxidized <span />