Answer:

Explanation:
When a projectile is fired upwards with some initial speed then the it reaches the top of the projectile and then falls back to the ground.
According to the question we need to find the work done by the gravity which is acting downwards for the projectile when it is at a position just about to hit the ground in course of falling down.
As we know that work is given as:

here:
force of gravity on the object (which is acting downwards)
displacement of the object
- Here the work done by the gravity at an instant just before the projectile hits the earth will be negative as the displacement is in the direction opposite to the force of gravity.
Natural gas creates the least amount of pollution when it's burned
Answer:
a). V = 3.13*10⁶ m/s
b). T = 1.19*10^-7s
c). K.E = 2.04*10⁵
d). V = 1.02*10⁵V
Explanation:
q = +2e
M = 4.0u
r = 5.94cm = 0.0594m
B = 1.10T
1u = 1.67 * 10^-27kg
M = 4.0 * 1.67*10^-27 = 6.68*10^-27kg
a). Centripetal force = magnetic force
Mv / r = qB
V = qBr / m
V = [(2 * 1.60*10^-19) * 1.10 * 0.0594] / 6.68*10^-27
V = 2.09088 * 10^-20 / 6.68 * 10^-27
V = 3.13*10⁶ m/s
b). Period of revolution.
T = 2Πr / v
T = (2*π*0.0594) / 3.13*10⁶
T = 1.19*10⁻⁷s
c). kinetic energy = ½mv²
K.E = ½ * 6.68*10^-27 * (3.13*10⁶)²
K.E = 3.27*10^-14J
1ev = 1.60*10^-19J
xeV = 3.27*10^-14J
X = 2.04*10⁵eV
K.E = 2.04*10⁵eV
d). K.E = qV
V = K / q
V = 2.04*10⁵ / (2eV).....2e-
V = 1.02*10⁵V
Answer:
Mass of the planet = 6.0 × 
Explanation:
Time period = 2π (R + h) / v
Orbital speed (v) = √GM / (R + h)
T² = 4π² (R + h)² / (GM/ (R + h))
= 4π² (R + h)³ / GM
making m the subject of the formula
m = 4π² (R + h)³ / GT²
= 4π² ( 6.38 ×
+ 230 × 10³ )³ / ( 6.67 ×
) × (89 × 60)²
= 4π² ( 6610000)³ / ( 6.67 ×
) × (89 × 60)²
= 5.99 × 
= 6.0 × 
Yes it is a force omg so smart