A projectile fired upward from the Earth's surface will usually slow down, come momentarily to rest, and return to Earth. For a certain initial speed, however it will move upward forever, with its speed gradually decreasing to zero just as its distance from Earth approaches infinity. The initial speed for this case is called escape velocity. You can find the escape velocity v for the Earth or any other planet from which a projectile might be launched using conservation of energy. The projectile of mass m leaves the surface of the body of mass M and radius R with a kinetic energy Ki = mv²/2 and potential energy Ui = -GMm/R. When the projectile reaches infinity, it has zero potential energy and zero kinetic energy since we are seeking the minimum speed for escape. Thus Uf = 0 and Kf = 0. And from conservation of energy,
Ki + Ui = Kf + Uf
mv²/2 -GMm/R = 0
∴ v = √(2GM/R)
This is the expression for escape velocity.
Answer:
Explanation:
500 W = 500 J/s
500 J/s(2 min(60 s/min) = 60000 J
Answer:
Explanation:
The force of static friction acting on the box is the frictional force;
Frictional force Ff = Wsin theta (force acting along the ramp)
W is the gravitational force known as the weight
Ff = 112.1sin42°
Ff = 112.1(0.6691)
Ff = 75.00N
Hence he force of static friction acting on the box if box has a gravitational force of 112.1 N id 75.00N
<span>1 cal = 4,185 J
1 kcal = 1*10^3 cal
or
=1000 cal</span>
Answer:
m = 1.5 kg
Explanation:
Data:
- Aceleration (a) = 8 m/s²
- Force (F) = 12 N
- Mass (m) = ?
Use formula:
Replace in the formula:
Equate the newtons:
Simplify m/s²:
It divides:
What is the mass of the train?
The mass of the train is <u>1.5 kilograms.</u>
