<span>d
The mass is doubled which means that both the momentum and kinetic energy are also doubled. Also the normal force that's acting along with the coefficient of kinetic friction is also doubled. So the friction that's working to slow down the crate is doubled. So the crate will have double the kinetic energy that needs to be dissipated, but the rate of dissipation is also doubled, so the total time required to dissipate the kinetic energy is the same. And since both crates start out with the same velocity and since they'll lose energy (and velocity) at the same proportional rate, they'll take the same distance to slide to a stop.</span>
Answer:
Explanation:
If an object is moving, it is said to have kinetic energy (KE). Potential energy (PE) is energy that is "stored" because of the position and/or arrangement of the object. The classic example of potential energy is to pick up a brick. When it's on the ground, the brick had a certain amount of energy.
Option D is correct. The speed at which the earth's surface moves because of the earth's rotation will then be equivalent to -10³ km/hr
Speed is a body is defined as the ratio of the distance with respect to the time taken by the body. Mathematically:
Speed = Distance/Time
GIven the following
Distance = 104km/hr
If it is 6:00 p.m. in New York, it is 7:00 a.m. of the next day of the week in Tokyo, this means that the time difference between New York and Tokyo is 11 hours.
Time = -11 hours
Get the required speed
Speed = 104/-11
Speed = -9.454545
Speed = -10km/hr
The speed at which the earth's surface moves because of the earth's rotation will then be equivalent to -10³ km/hr
Learn more here: brainly.com/question/2583051
To develop this problem it is necessary to apply the concepts related to Gravitational Potential Energy.
Gravitational potential energy can be defined as

As M=m, then

Where,
m = Mass
G =Gravitational Universal Constant
R = Distance /Radius
PART A) As half its initial value is u'=2u, then



Therefore replacing we have that,

Re-arrange to find v,



Therefore the velocity when the separation has decreased to one-half its initial value is 816m/s
PART B) With a final separation distance of 2r, we have that

Therefore




Therefore the velocity when they are about to collide is 
If the velocity of the train is v=s/t, where s is the distance and t is time, then v=400/5=80m/s. To get the vertical component of the velocity we need to multiply the velocity v with a sin(α): Vv=v*sin(α), where Vv is the vertical component of the velocity and α is the angle with the horizontal. So:
Vv=80*sin(10)=80*0.1736=13.888 m/s.
So the vertical component of the velocity of the train is Vv=13.888 m/s.