work done is product of force and displacement of point of application of force
so here we have to check the product of force and displacement both
Now we will put the least to maximum work in the following order
1. -A man exerts strenuous effort in pushing a stationary wall
2. -A flea pushes a speck of dirt 1 cm
3. -A farmer pushes a 2 kg wheelbarrow 20 m
4. -A cannon launches a 3 kg cannonball a distance of 200
5. -A 2000 kg car travels 400 m down a road
6. -Space shuttle Atlantis launches from the ground into near-Earth orbit
ANSWER
EXPLANATION
Parameters given:
Mass of the student, M = 70 kg
Mass of the textbook, m = 1 kg
Distance, r = 1 m
To find the gravitational force acting between the student and the textbook, apply the formula for gravitational force:
where G = gravitational constant
Therefore, the gravitational force acting between the student and the textbook is:
That is the answer.
The formula of the kinetic energy is:
where m is a mass of the object, v is speed of the object at the moment of time. So we have:
The answer is
2000 Joules.
Answer:
11:1
Explanation:
At constant acceleration, an object's position is:
y = y₀ + v₀ t + ½ at²
Given y₀ = 0, v₀ = u, and a = -g:
y = u t − ½g t²
After 6 seconds, the ball reaches the maximum height (v = 0).
v = at + v₀
0 = (-g)(6) + u
u = 6g
Substituting:
y = 6g t − ½g t²
The displacement between t=0 and t=1 is:
Δy = [ 6g (1) − ½g (1)² ] − [ 6g (0) − ½g (0)² ]
Δy = 6g − ½g
Δy = 5½g
The displacement between t=6 and t=7 is:
Δy = [ 6g (7) − ½g (7)² ] − [ 6g (6) − ½g (6)² ]
Δy = (42g − 24½g) − (36g − 18g)
Δy = 17½g − 18g
Δy = -½g
So the ratio of the distances traveled is:
(5½g) / (½g)
11 / 1
The ratio is 11:1.
<span>The correct option is C. Gravity, and the complete sentence is: "The force of gravity is the force at which the Earth attracts another object towards itself". In fact, the force of gravity between two objects is given by
</span>
<span>
where G is the gravitational constant, m1 and m2 the masses of the two objects, r their separation. If we take the Earth as one of the two objects, then m1 represents the Earth's mass, m2 the mass of the object and r the distance between the center of Earth and the object, and F is the gravitational force at which the Earth attracts the object.</span>