Answer:
48kg
Explanation:
i could be wrong if i am srry
Answer:
a. 
b. 
Explanation:


, 
radius earth = 6371 km
mass earth = 5,972*10^24 kg
a.



b.






Efficiency η of a Carnot engine is defined to be:
<span>η = 1 - Tc / Th = (Th - Tc) / Th </span>
<span>where </span>
<span>Tc is the absolute temperature of the cold reservoir, and </span>
<span>Th is the absolute temperature of the hot reservoir. </span>
<span>In this case, given is η=22% and Th - Tc = 75K </span>
<span>Notice that although temperature difference is given in °C it has same numerical value in Kelvins because magnitude of the degree Celsius is exactly equal to that of the Kelvin (the difference between two scales is only in their starting points). </span>
<span>Th = (Th - Tc) / η </span>
<span>Th = 75 / 0.22 = 341 K (rounded to closest number) </span>
<span>Tc = Th - 75 = 266 K </span>
<span>Lower temperature is Tc = 266 K </span>
<span>Higher temperature is Th = 341 K</span>
Answer:
it is constant because there is not any force that oppose the horizontal motion
but the vertical velocity is not constant because there is a gravitational force that oppose the motion .
#1
for the block of mass 5 kg normal force is given as


friction force is given as


Net force is given as


now we know that



#2
Normal force is given as



now we know that


as object moves with constant velocity

now for coefficient of friction we can use



#3
net force upwards is given as

mass is given as

now as per newton's law we can say



#4
As we know that when block is sliding on rough surface
part a)
net force = applied force - frictional force




part b)
for coefficient of friction we can use


here normal force is given as

now we have

#5
if an object is initially at rest and moves 20 m in 5 s
so we can use kinematics to find out the acceleration



now net force is given as


#6
an object travelling with speed 25 m/s comes to stop in 1.5 s
so here acceleration of object is given as


now the force is gievn as

