25,000 Feet = 7620m
PE = mgh where m is mass, g is gravity accel: 9.8 n h is height
= 90 x 9.8 x 7620
= 6720840J
= 6.72MJ
F = ma where m is mass, a is accel = gravity = 9.8
= 90 x 9.8
= 882N
Accel = gravity = 9.8m/s^2
KE = 1/2mv^2 where m is mass n v is vel
if no wind resistance, PE leaving airplane = KE at net
6720840 = 1/2 x 90 x v^2
v^2 = 149352
v = 386.5m/s
Answer:
The answer is below
Explanation:
The main difference between a liquid and a gas is that when a liquid is under pressure, its volume "won't change apparently. The reason is that the distance between the molecules of a liquid is relatively small, and the molecules of a liquid extensively withstand the compressive forces. This is similar to the distance between the molecules of a solid."
Pt-200 is most likely to undergo beta-minus decay. Two four given isotopes of platinum are radioactive. Pt-192 is a stable isotope.
Answer: radiant energy
Explanation:
The energy in electromagnetic waves is sometimes called radiant energy.
Answer:
Work done by the spring is negative
Explanation:
We can answer this question by thinking what is the force acting on the box.
In fact, the force acting on the box is the restoring force of the spring, which is given by Hooke's Law:

where
k is the spring constant
x is the displacement of the box with respect to the equilibrium position of the spring
The negative sign in the equation indicates that the direction of the force is always opposite to the direction of the displacement: so, whether the spring is compressed or stretched, the force applied by the spring on the box is towards the equilibrium position.
The work done by the restoring force is also given by

where
F is the restoring force
x is the displacement
is the angle between the direction of the force and the displacement
Here we know that the force is always opposite to the displacement, so

Which means that the work done by the spring is always negative, since the direction of the restoring force is always opposite to the direction of motion.