Answer:
Explanation:
A component of 150 N in vertical direction will reduce the magnitude of reaction force.
reaction force exerted by the floor
= mg - 150 sin 30
where m is mass of the crate .
the magnitude of the horizontal component of the 150-newton force
150 cos30
= 130 N
This force tries to pull the crate in forward direction with acceleration but it has no acceleration . It is so because frictional force of equal magnitude acts on it in opposite direction which makes the net force acting on it equal to zero.
Hence frictional force is equal to 150 cos 30.
= 130 N .
Answer: The correct answer is "the speed of the wave becomes four times".
Explanation:
The relation between the speed, frequency and the wavelength is as follows:
v=f\lambda
Here, v is the speed of the wave, f is the frequency and \lambda is the wavelength.
The speed of the sound wave is directly proportional to the frequency.
In the given problem, if the speed of the sound wave is increased four times then the speed of the sound becomes four times.
Therefore, the speed of the sound wave becomes four times.
Electrostatic forces are non-contact forces; they pull or push on objects without touching them
Answer:
Explanation:
Force on electron in an electric field E = eE where E is electric field .
acceleration = eE / m where m is mass of electron .
Putting the values
4 x 10⁶ = 1.6 x 10⁻¹⁹ x E / 9.1 x 10⁻³¹
E = 22.75 x 10⁻⁶ N/C
The direction of electric field will be towards west ( opposite to east )
because of negative charge on electron .
