Answer:
B) Because the Space Station is constantly in free-fall around the Earth.
Explanation:
Anything that is falling experiences an upward force on them. For example when a person is going down in a lift they will experience something that is pushing them upwards. This happens due to the fact that the total acceleration the body is feeling is less than the acceleration due to graviity.
The force on a body which is falling is

Where,
m = Mass of object
g = acceleration due to gravity
a = acceleration the object is experiencing.
a = g. So, the force becomes zero and the object experiences weightlessness.
Hence, the astronauts in the space station experience weightlessness due to fact that the Space Station is constantly in free-fall around the Earth.
Answer:
The driver hits the stationery dog because the applied force is less than required force
Explanation:
Kinetic energy will be given by
where m is the mass of the vehicle and v is the speed/velocity of the vehicle.
Substituting 800 Kg for m and 20 m/s for v we obtain

Frictional force by vehicle pads is given by
where d is the distance moved
Substituting 160000 for KE and 50 m for d we obtain

Therefore, the vehicle hits the dog since the required force is 3200N but the driver applied only 2000 N
Answer: Option (c) is the correct answer.
Explanation:
Language is defined as a medium through which a person can deliver its thoughts, ideas, or perceptions to one or more individuals.
For example, Leslie is feeling sad and that is why she is crying. Therefore, listening a cry sound her friend sitting in the next room came immediately to console her.
Hence, sound of crying is also a sign of language that tells Leslie is sad about something.
Therefore, we can conclude that the statement languages use spoken sounds, written words, and signs to represent ideas and events, is true about language.
The answer is ultra violet radiation. From the air
Answer:
El avión recorrió 45 km en los 180 s.
Explanation:
La relación entre velocidad, distancia y tiempo se da de la siguiente manera;

Por lo cual los parámetros dados son los siguientes;
Velocidad = 900 km/h = 250 m / s
Tiempo = 180 s
Estamos obligados a calcular la distancia recorrida
De la ecuación para la velocidad dada arriba, tenemos;
Distancia recorrida = Velocidad pf viaje × Tiempo de viaje
Distancia recorrida = 900 km/h × 180 s = 900
Distancia recorrida = 900 km/h × 1 h/60 min × 1 min/60 s × 180 s = 45 km
Por lo tanto, el avión viajó 45 km en 180 s.