D (it was produced by cyanobacteria)!!!
Answer:
Repulsion is the sure test for magnetism because it occurs only when two like poles of a magnet exist while the attraction phenomenon can occur between two unlike poles of a magnet and also between a magnet and a magnetic material means if there are two magnets they will attract each other and suppose if one material
Hi there,
Matter is sometimes invisible. Most invisible matters are gas because it consists of tiny air molecules.
Hope this helps!
Sincerely,
Dus4nR
Explanation:
Given data
Mass of skier m=65kg
Height of slope =80m
Potential energy possessed by the skier (positive work done) =12000J
Analysing his energy at half way point on the hill
Potential energy will be equal to kinetic energy
Applying the conservative principles of energy when the skier is at half way point in the hill
I.e
mgh= 1/2mv²
The masses will cancel out
gh=v²
Given g= 9.81m/s²
Let's solve for the velocity
v²=9.81*80
v=√784.8
v=28.0m/s
Now we can solve for the kinetic energy
KE= 1/2mv²
KE =1/2*60*28²
KE =47063.9/2
KE=23531.9J
Hence we can calculate the energy gained by the skier during his movement
Energy gained = KE-PE
= 23531.9-12000
= 11531.9J
B. Thermal energy is the energy that warms the earths surface.
