To solve this problem we will apply the concepts related to gravity according to the Newtonian definitions. From finding this value we will use the linear motion kinematic equations to find the time. Our values are
Comet mass 
Radius 
Rock was dropped from a height 'h' from surface = 1m
The relation for acceleration due to gravity of a body of mass 'm' with radius 'r' is

Where G means gravitational universal constant and M the mass of the planet


Now calculate the value of the time




The time taken for the rock to reach the surface is t = 87.58s
Answer:
The answer is "between 20 s and 30 s".
Explanation:
Calculating the value of positive displacement:


Calculating the value of negative displacement upon the time t:




That's why its value lie in "between 20 s and 30 s".
Sometimes arithmetic problems can be solved much more easily using the dimensional analysis approach. You focus on the units of the given information. Then, you manipulate them applying the laws of algebra where like units cancel, in order to end up with the unit of the unknown.
Given:
-50 nc/step
31 steps
Unknown: charge
Thus,
Charge = -50 nc/step * 31 steps =<em> -1550 nc</em>
Answer:
a = 4.72 m/s²
Explanation:
given,
mass of the box (m)= 6 Kg
angle of inclination (θ) = 39°
coefficient of kinetic friction (μ) = 0.19
magnitude of acceleration = ?
box is sliding downward so,
F - f = m a
f is the friction force
m g sinθ - μ N = ma
m g sinθ - μ m g cos θ = ma
a = g sinθ - μ g cos θ
a = 9.8 x sin 39° - 0.19 x 9.8 x cos 39°
a = 4.72 m/s²
the magnitude of acceleration of the box down the slope is a = 4.72 m/s²
Answer:
a) v = 75 ft / s
, b) v = 55 ft / s
, c) Δx = 1000 ft
Explanation:
We can solve this exercise with the expressions of kinematics
a) average speed is defined as the distance traveled in a given time interval
v = (x₂-x₁) / (t₂-t₁)
v = (550 - 400) / (10 -8)
v = 75 ft / s
b) we repeat the calculations for this interval
v = (550 - 0) / (10 -0)
v = 55 ft / s
c) we clear the distance from the average velocity equation
Δx = v (t₂ -t₁)
Δx = 100 (20-10)
Δx = 1000 ft