Answer:
Explanation:
Let after time t , Tina catches up David .
Distance travelled by them are equal ,
Distance travelled by Tina
s = ut + 1/2 a t²
= .5 x 2.10 t²
= 1.05 t²
Distance travelled by David
= 30 t ( because of uniform velocity )
1.05 t² = 30t
t = 28.57 s
Distance travelled by Tina
= 1/2 a t²
= .5 x 2.10 x 28.57²
= 857 m approx.
Answer:
Explanation:
Initial speed, v = 10 x 10^3 m/s
Mass of the earth, M = 6 x 10^24 kg
Radius of the earth, R = 6.4 x 10^6 m
Maximum from the surface of earth, h = ?
Let m = Mass of the projectile
Solution:
Potential energy at maximum height = ( Potential + Kinetic energy ) at the surface
![-G M m / ( R + h )=- G M m / R + (1/2) m v^2](https://tex.z-dn.net/?f=-G%20M%20m%20%2F%20%28%20R%20%2B%20h%20%29%3D-%20G%20M%20m%20%2F%20R%20%2B%20%281%2F2%29%20m%20v%5E2)
![- G M / ( R + h ) = - G M / R + (1/2) v^2](https://tex.z-dn.net/?f=-%20G%20M%20%2F%20%28%20R%20%2B%20h%20%29%20%3D%20-%20G%20M%20%2F%20R%20%2B%20%281%2F2%29%20v%5E2)
![-2\times G M / ( R + h ) = ( - 2 G M / R ) + v^2](https://tex.z-dn.net/?f=-2%5Ctimes%20G%20M%20%2F%20%28%20R%20%2B%20h%20%29%20%3D%20%28%20-%202%20G%20M%20%2F%20R%20%29%20%2B%20v%5E2)
=![( (- 2\times 6.67\times10^{-11}\times6\times10^{24}) /(6.4\times10^6)} +10000^2](https://tex.z-dn.net/?f=%28%20%28-%202%5Ctimes%206.67%5Ctimes10%5E%7B-11%7D%5Ctimes6%5Ctimes10%5E%7B24%7D%29%20%2F%286.4%5Ctimes10%5E6%29%7D%20%2B10000%5E2)
=![-2.50625\times10^7 J](https://tex.z-dn.net/?f=-2.50625%5Ctimes10%5E7%20J)
![=- 8\times10^{14} / ( R + h )=-2.50625\times 10^7](https://tex.z-dn.net/?f=%3D-%208%5Ctimes10%5E%7B14%7D%20%2F%20%28%20R%20%2B%20h%20%29%3D-2.50625%5Ctimes%2010%5E7)
![R+h=31.92\times10^{6}](https://tex.z-dn.net/?f=R%2Bh%3D31.92%5Ctimes10%5E%7B6%7D)
![h=31.92\times10^{6}-6.4\times10^6](https://tex.z-dn.net/?f=h%3D31.92%5Ctimes10%5E%7B6%7D-6.4%5Ctimes10%5E6)
You need to have the Mass and velocity
Its true the ionic compounds have a higher melting point