Answer:
Explanation:
Assume that the distance travelled initially is d.
In order to stop the block you need some external force which is friction.
If we use the law of energy conservation:
a)
Looking at the formula you can see that the mass doesn't affect the distance travelled, as lng as the initial velocity is constant (Which indicates that the force must be higher to push the block to the same speed) therefore the distance is the same.
b) If the velocity is doubled, then the distance travelled is multiplied by 4, because the distance deppends on the square of the velocity.
(a) -1620.8 J
The initial kinetic energy of the skateboarder is:
where m is the skateboarder's mass and u his initial speed;
While the final kinetic energy is
where v is his final speed.
So the change in kinetic energy is
According to the work-energy theorem, the change in mechanical energy (kinetic+potential) of the skateboarder is equal to the work done on it:
where
is the work done by the skateboarder on himself
is the work done by friction
is the change in gravitational potential energy
Solving for 
,
(b) 2.97 m
The change in potential energy of the skateboarder can be written as
where
m = 55.6 kg is the mass
g = 9.8 m/s^2 is the acceleration of gravity
is the change in vertical height of the skateboarder
Solving for ,
Where the negative sign means the skateboarder has moved downwards. Since we are interested only in the absolute value, the answer is
h = 2.97 m
Answer: Pπr2
Explanation: Force is any interaction that affects an object,that if not opposed or treated will cause some changes in the object. Pressure is directly proportional to force,which means an increase in force will create a corresponding increase in the pressure of a system.
The force on the cloth will be The PRESSURE EXERTED ON THE CLOT (P) *THE PI( which is the RATIO of the circumference of the cylinder i.e3.14159) *the square of the ratio. Which is Pπr2.
The atomic mass of sodium (Na) is 22.98977
Answer: Because The spectra provided evidence to explain why the sun's atmosphere is so much hotter than its surface. ... Clear evidence now suggests that the heating mechanism depends on regular, but intermittent explosive bursts of heat, rather than on continuous gradual heating.
Explanation:
