Answer
Calculate the amount of heat needed to melt 2.00 kg of iron at its melting point (1809 K), given that: ?Hfus = 13.80
Answer:
speed are different at different places
Explanation:
because it's top speed is 50km/h,so it's initial speed may be less. when it covers some distance it's speed changes again. then we have given a mean speed .mean speed means sum of all speed divided by sum of total time.so the mean speed and final speed differs from each other
Answer: - 7500N
Explanation:
Given the following :
Initial Velocity of car = 108km/hr
Time taken to stop after applying brakes = 4s
Mass of passengers in car = 1000kg
Force exerted by the brakes on the car =?
After 4s, then final Velocity (V) = 0
Initial Velocity (u) of the car = 108km/hr
108km/hr = (108 × 1000)m ÷ (3600)s = 30m/s
Force exerted = mass(m) × acceleration(a)
Acceleration of car = Change in Velocity with time
a = (v - u) / t
a = (0 - 30) / 4
a = - 30/ 4
a = - 7.5m/s^2
Therefore,
Force exerted = mass(m) × acceleration(a)
Force exerted = 1000kg × (-7.5)m/s^2
Force exerted = - 7500N