Answer:
Av = 25 [m/s]
Explanation:
To solve this problem we must use the definition of speed, which is defined as the relationship between distance over time. for this case we have.
where:
Av = speed [km/h] or [m/s]
distance = 180 [km]
time = 2 [hr]
Therefore the speed is equal to:
Now we must convert from kilometers per hour to meters per second
Answer:
Explanation:
A. The earth about its axis:
The earth makes one revolution in 24 hours. to know the number of revolutions per second it makes, we need to convert hours to seconds and the revolution to rad.
B. The minute hand of the clock makes one revolution in 60 minutes
To convert this to rad per second, we have
C. The hour hand of a clock completes one revolution in 12 hours
D. an egg beater turning at 300 rpm.
A) Time needed: 6.24 s
B) Time needed: 2.86 s
Explanation:
A)
In this part, we are told that the power if the engine is constant. The power of the engine is given by
where
W is the work done
t is the time
This means that the power of the engine is proportional to the work done, and therefore, to the kinetic energy of the car:
where m is the mass of the car and v its velocity.
SInce power is constant, we can write:
where:
is the time the car needs to accelerates to
is the time the car needs to accelerate to
Therefore, solving for ,
B)
First of all, we have to calculate the acceleration of the car. We can do it using the following equation:
where:
u = 0 is the initial velocity
is the final velocity
t = 1.40 s is the time elapsed
Substituting, we find the acceleration:
In this part, we are told that the force exerted by the engine is constant: according to Newton's second law, acceleration is proportional to the force,
This means that the acceleration is also constant.
Now we want to find how long the car takes to accelerate to a final velocity of
From an initial velocity of
u = 0
Using again the same suvat equation, and using the acceleration we found previously, we find:
Learn more about accelerated motion:
About power:
#LearnwithBrainly