The force ffrom the ground that holds the rock up and prevents her from falling through the gound, unless the ground breaks.
Ummmmmmmmmm is this what subject??????? Because I hv no idea unless u tell me a subject
Explanation:
Distance d=1.5×108 km=1.5×1011 m
Mass of the sun, m=2×1030 kg
Mass of the earth, M=6×1024 kg
Force of gravitation, F=G×d2m×M
F=6.7×10−11×(1.5×1011)22×1030×6×1024=3.57×1022 N
Answer:
a) the mass of the second car = 28000 kg
b) the amount of kinetic energy that was lost in the collision = 
Explanation:
Given that:
mass of the train car
= 6300 kg
speed of the train car
= 12.0 m/s
mass of the second moving car
= ???
speed of the second moving car
= 2.2 m/s
After strike;
they both move with a speed
= 4.00 m/s
a)
Using the conservation of momentum :







b)
To determine the amount of kinetic energy that was lost in the collision;
we will need to find the difference between the kinetic energy before the collision and after the collision;
i.e







Now; the kinetic energy that was lost in the collision is calculated as follows:




Formula for height
<span> r(t) = a/2 t² + v₀ t + r₀
</span><span> where
</span><span> a = acceleration = -32 ft/sec² (gravity)
</span><span> v₀ = initial velocity
</span><span> r₀ = initial height
</span><span> r(t) = -16t² + v₀ t + r₀
</span> <span>Tomato passes window (height = 450 ft) after 2 seconds:
</span><span> r(2) = 450
</span><span> -16(4) + v₀ (2) + r₀ = 450
</span><span> r₀ = 450 + 64 - 2v₀
</span><span> r₀ = 514 - 2v₀
</span><span> Tomato hits the ground (height = 0 ft) after 5 seconds:
</span><span> r(5) = 0
</span><span> -16(25) + v₀ (5) + r₀ = 0
</span> r<span>₀ = 16(25) - 5v₀
</span><span> r₀ = 400 - 5v₀
</span><span>
r₀ = 514 - 2v₀ and r₀ = 400 - 5v₀
</span> <span>514 - 2v₀ = 400 - 5v₀
</span><span> 5v₀ - 2v₀ = 400 - 514
</span> <span>3v₀ = −114
</span><span> v₀ = −38
</span><span> Initial velocity = −38 ft/sec (so tomato was thrown down)
</span><span> (initial height = 590 ft) </span>