A box of bananas weighing 40 N rests on a horizontal surface. The coefficient of static friction between the box and the surface
1 answer:
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Answer:
Explanation:
The only thing I can figure you need here is the accleration of the sled. The equation we need to find this is Newton's Second Law that says that sum of the forces acting on an object is equal to the object's mass times its acceleration. For us, that looks like this because of the friction working against the sled:
F - f = ma but of course it's much more involved than that simple equation! We have the F value as 230 N, and we have the mass as 105, but we do not have the frictional force, f, and we need it to solve for a in the above equation. We know that
f = μ where μ is the coefficient of friction, and
is the normal force, aka weight of the object. We will use the coefficient of friction and find the weight in order to fill in for f:
so
so the weight of the sled is
1.0 × 10³ with the correct number of sig dig there. Now to find f:
f = (.025)(1.0 × 10³) so
f = 25 to the correct number of sig fig. Now on to our "real" equation:
F - f = ma and
230 - 25 = 105a. We have to do the subtraction first, round, and then divide since the rules for addition and subtraction are different from the rules for dividing and multiplying.
230 - 25 will round to the tens place giving us 210. Then
210 = 105a. 210 has 2 sig figs in it while 105 has 3, so we will divide and round to 2 sig fig:
a = 2.0 m/sec²
Answer:
The force of gravity
Explanation:
Gravity was studied, by early scientists such as Copernicus and others, Galileo was the first to ensure that planets moved according to a physical equation that depended on a force that caused celestial bodies to move and interact with each other. But years later Newton based on studies conducted deciphering what Galileo assumed, he was able to find the equation of the force of gravity in any body in the universe. This equation depends on the masses of the two interacting bodies, the distance between them and a constant, which I call universal gravitation constant.
Fg = gravity force [N]
G = universal gravitation constant = 6.67*10^(-11) [N*m^2/kg^2]
m1 = mass of the 1st body [kg]
m2 = mass of the 2nd body [kg]
r = distance between the bodies [meters]
1. 168.1 Hz
To find the apparent frequency heard by the driver in the car, we can use the formula for the Doppler effect:
where
f is the original sound of the horn
v is the speed of sound
is the velocity of the observer (the driver and the car), which is positive if the observer is moving towards the source and negative if it is moving away
is the velocity of the sound source (the train), which is positive if the source is moving away from the observer and negative otherwise
In this problem we have, according to the sign convention used:
Substituting, we find:
2.
The speed of light can be calculated as
where
d is the distance travelled
t is the time taken
In this problem:
is the total distance travelled by the laser beam (twice the distance between the Earth and the Moon)
t = 2.60 s is the time taken
Substituting in the formula,