جسم كتلته (m=0.9 kg)  معلق بخيط مهمل الكتله طوله (L=3m) ويتحرك في دائرة افقية بسرعة مناسبة مقدارها (v=3m/s). ما مقدار القوة التي يؤثر بها الخيط في الجسم ؟

9 N

Explanation:

The centripetal force F is F = mrω^2 = (mv^2)/r where m is mass, r is radius of the curve, ω is angular velocity and v is tangential velocity.

In this case, m = 0.5kg, r = 0.5m, v = 3m/s

So F = [0.5kg(3m/s)^2]/0.5m = 9kg-m/s^2 which is 9N

cell differentiation  is how generic embryonic  cells  become specialized  cells. this occurs  through a process called gene expression. gene expression is the specific combination of genes that are turned on or off (expressed or repressed), and this is what dictates how a  cell  functions.

explanation: