Answer: the rarest element is Francium. J is not on the periodic table. also Dmitri Mendeleev proposed the periodic table.
Explanation: Kinda looked the last one up.
Answer:
0.45 miles
Explanation:
since, car will be running on the edge of track, distance covered in one lap by car will be equal to circumference of track.\
we will use value of pi as 22/7
Circumference for any circular shape is given by 
Hence, in one lap distance will be covered
in 7 laps 
distance will be covered.
but is given that 7 laps should be equal to 10 miles
so 10 miles will be equal to 
Thus, diameter of track will be 0.45 miles to meet the requirement.
Answer:
Explanation:
A body has zero velocity and non- zero acceleration. It is possible as at the time when a body thrown upwards is at the top of the height. In that case velocity is zero but acceleration is equal to g.
A body travels with northward velocity but southward acceleration . it is also possible as in case when a body is going with northward velocity but when break is applied acceleration becomes southward.
A body travels with northward velocity and northward acceleration . it is also possible as in case when a body is going with northward velocity and when accelerator is applied . Acceleration becomes northward.
A body travels with constant velocity and a constant non zero acceleration . It is not possible . When there is acceleration , there must be a a change in velocity either in terms of magnitude or direction or both.
A body travels with a constant acceleration and a time varying velocity. It is possible. Time varying velocity represents acceleration.
Answer:
14.2
Explanation:
find horizontal force of the weight = 2.5kg x 9.8 Sin30 = 12.3 N
to prevent the sliding she needs to pull horizontally
Fh = 12.3 /Cos 30 =14.2N
