Answer:
(That an object must be made out of metal to be attracted, but not all metals are attracted.) Metals such as iron, nickel, and cobalt are attracted to magnets. Steel has iron in it, so it is also attracted to magnets.
Explanation:
basically magnets
As per Newton's II law we know that
here we know that
so here we will have
so here if we need to increase the acceleration we need to increase the applied force while on increasing the mass or on increasing the friction force the acceleration will decrease.
So here correct answer will be
<em>A) force on the object.</em>
Answer:
decibels (dB)
Explanation:
The sound intensity level is a quantity derived from the sound intensity.
The intensity of a wave is defined as the power of the source of the wave divided by the area through which the power of the wave is spread, mathematically:
where
P is the power of the source
is the surface area over which the wave spreads (assuming that the wave propagates in all directions, it corresponds to the surface area of a sphere of radius , where r is the distance between the source of the wave and the observer)
For sound waves, the intensity is often expressed using another unit, called decibel (dB), defined as follows:
where
is the sound intensity level in decibels
I is the intensity of the sound wave
is the threshold intensity of a sound that a person can normally hear.
Answer:
B: leaving metal outside in the rain until rust forms an it's surface
Answer:
(a) 161.57 N
(b) 0.958 m/s^2
Explanation:
Force applied, F = 220 N
mass of crate, m = 61 kg
μ = 0.27
(a) The magnitude of the frictional force,
f = μ N
where, N is the normal reaction
N = m x g = 61 x 9.81 = 598.41 N
So, the frictional force, f = 0.27 x 598.41
f = 161.57 N
(b) Let a be the acceleration of the crate.
Fnet = F - f = 220 - 161.57
Fnet = 58.43 N
According to newton's second law
Fnet = mass x acceleration
58.43 = 61 x a
a = 0.958 m/s^2
Thus, the acceleration of the crate is 0.958 m/s^2.