25 kg
Explanation:
we can calculate the mass of the crate by using the Newton's second law:
where
F is the force acting on the crate
m is the mass
a is the acceleration
In this problem, 
and 
, so we can re-arrange the equation above to calculate the mass of the crate:
Ordinary cells can convert chemical energy to electrical energy only, but rechargeable cells can also store electrical energy into chemical energy and vice versa. You will study more about it in your higher classes. secondary cells can be recharged and used again but dry cells cannot be recharged.
Answer:
Angular speed, 
Explanation:
It is given that,
The top of the leaning bell tower at Pisa, Italy, moved toward the south at an average rate of, v = 1.2 mm/yr
Velocity, 
Height of the tower, h = 55 m
The height of the tower is equivalent to the radius. Let 
is the angular speed of the tower’s top about its base. The relation between the angular speed and the angular speed is given by :
So, the average angular speed of the tower’s top about its base is 
. Hence, this is the required solution.
<span>In a
real machine, the work output is always less than the work input is true. The answer
is letter A. it follows the law of entropy where no energy can be converted completely
into work. Under this law, Carnot’s theorem states that Carnot’s engine can
perform 100% of work. However, no such engine has ever succeeded the conversion
of work into 100%. The greatest efficiency so far is at 80%. Because there will always be factors that
could affect the conversion of work. </span>
density = mass/volume = 100kg/10ml = 10kg/ml
voluime = mass/density = 50g/2 g/ml = 25 ml
mass = density x volume = 2x55 = 110 kg
