Answer:
or -0.000250 C
Explanation:
The field points downward, which is the direction of a positive charge. In order for the penny to rise, it has to have a negative charge since its direction is opposite that of the field.
To calculate the magnitude of the charge:
The penny is to accelerate upward so it must overcome gravity. Hence, the net force to cause it to accelerate it upward is the difference between the electrostatic force and its weight.






Now, the electric field intensity is given by

where q = charge

to 3 significant figures.
In standard form, q =
The negative sign indicates it has a negative charge, as explained initially.
Answer:
Vertical component of velocity is 9.29 m/s
Explanation:
Given that,
Velocity of projection of a projectile, v = 22 m/s
It is fired at an angle of 22°
The horizontal component of velocity is v cosθ
The vertical component of velocity is v sinθ
So, vertical component is given by :



Hence, the vertical component of the velocity is 9.29 m/s
Answer: b. infrared
Explanation:
The visible light with the smaller frequency is associated with the color red.
While the blue is the one with the larger frequency.
Now, as the name says, infrared waves are the ones with a frequency just below the one of the red visible light.
Where the frequency of the red light is something around (4.3*10^14 Hz)
and the frequency of the infrared waves is in the range between (10^12 Hz and 10^14 Hz)
Then the correct option is b, infrared.