Acceleration is the rate of change of velocity, so can be calculated by:
a = v2 - v1 / t where v2 and v1 are the final and initial velocities of the object respectively and t is the time taken. Therefore the acceleration is:
a = 30 m/s - 20 m/s / 2.0 s = 10 m/s / 2.0 s = 5 m/(s^2)
Hope this helps!
Answer:
B
Explanation:
Friction always eventually stops whatever is in motion.
Answer:




So then we see that the final luminosity decrease by a factor of 625 so then the correct answer for this case would be:
B. Decreases by a factor of 625
Explanation:
For this case we can use the formula of luminosity in terms of the radius and the temperature given by:

Where L_i = initial luminosity, r= radius and T = temperature.
We know that we decrease the radius by a factor of 100 and the temperature increases by a factor of 2 so then the new luminosity would be:




So then we see that the final luminosity decrease by a factor of 625 so then the correct answer for this case would be:
B. Decreases by a factor of 625
Answer:
Force of gravity, F = 0.74 N
Mass of an object, m = 1.2 kg
Distance above earth's surface, 
Mass of Earth, 
Radius of Earth, 
We need to find the force of gravity above the surface of Earth. It is given by :

R = r + d
R = 25370000 m

F = 0.74 N
So, the force of gravity on the object is 0.74 N. Hence, this is the required solution.