Speed=distance/time, rearranging gives speed*time=distance therefore the first section of the journey yielded a total distance of 40km, the second journey was stated to be 20km which was completed in (20/30)*60=40minutes. Therefore the total journey was 60km which was completed in 1hr40 minutes so the average speed was (60/1.66..)=36km/h.
Answer:
When the string moves, it creates a very small change in the distance to the next point, th
Explanation:
When the string moves, it creates a very small change in the distance to the next point, this generates a restoring force that tends to push the string back, this small disturbance propagates along the string and is what creates the pulse.
This is similar to what happens when a spring is stretched and a restoring force is generated shaved by the law of shortening.
F = k Dx
A 1.5 kg bird is gliding at a height of 12 m with a speed of 3.8m/s. The kinetic energy of the bird is 10.83 joules.
Explanation:
Kinetic energy can be defined as,The kinetic energy (KE) of an object is the energy that the object possesses due to its motion.
The Kinetic energy can be calculated by using formula,
Kinetic Energy: KE = 1/2 (mv 2)
Where, m = Mass, v = Velocity.
Here in this case the bird mass is 1.5kg and is gliding with velocity 3.8m/s
hence, KE= 1/2*(1.5)×(3.8)^2
=0.5×1.5×3.8×3.8
=10.83Joules
Answer:

Explanation:
The total energy of the satellite when it is still in orbit is given by the formula

where
G is the gravitational constant
m = 525 kg is the mass of the satellite
is the Earth's mass
r is the distance of the satellite from the Earth's center, so it is the sum of the Earth's radius and the altitude of the satellite:

So the initial total energy is

When the satellite hits the ground, it is now on Earth's surface, so

so its gravitational potential energy is

And since it hits the ground with speed

it also has kinetic energy:

So the total energy when the satellite hits the ground is

So the energy transformed into internal energy due to air friction is the difference between the total initial energy and the total final energy of the satellite:
