If you'r referring to some objects, it means that the mass of the object is less than the water so it floats. If the mass of an object is greater than the mass of the water, it will sink. Compare it to a balloon, helium makes it rise, while normal air makes it sink.
When Alana moving 19km/h, a stationary object will be perceived by her as moving toward her with 19km/h velocity. If the object is not stationary(velocity isn't zero), the speed will increase by the object velocity.
the relative speed of the tennis ball=
the speed of Alana + true speed of the tennis ball
19km/h+ 11km/h= 30km/h
Answer:
Explanation:
Suppose when bucket is half full it has a mass of 2 m rotating in a circle of radius r
When Bucket is quarter full then it has a mass of m rotating in a circle of radius r.
When an object moves in a circular path then it experiences an inward force which is given by

where v=velocity of bucket
Force in case 2 is given by

Thus
therefore force required in half bucket is more than force required in quarter bucket full.
Because no sunlight can penetrate it
Answer: something must drop it over
Explanation: