Answer:
C
Sign-Negative
Explanation:
We are given that
Electric field =
(Radially downward)
Acceleration=
(Upward)
Mass of charge=3 g=
kg
1kg=1000g
We have to find the magnitude and sign of charge would have to be placed on a penny .
By newton's second law


Substitute the values then we get

Substitute the values then we get




C
Sign of charge =Negative
Because electric force acting in opposite direction of electric field therefore,charge on penny will be negative.
initial speed of 226000 m/s
acceleration of 4.0 x 1014 m/s2,
speed of 781000 m/s
What is Acceleration?
- Acceleration is a rate of change of velocity with respect to time with respect to direction and speed.
- A point or an object moving in a straight line is accelerated if it speeds up or slows down.
- Acceleration formula can be written as,
a = (v - u ) / t m/s²
As we have to find the time taken, the formula can be altered as,

where, t - time taken to reach a final speed
v - final velocity
u - initial velocity
a - acceleration.
Substituting all the given values,

= 1.3875 × 10⁻⁹ seconds.
So, taken to reach the final speed is found to be 1.3 × 10⁻⁹ 8iH..
Anything less dense than water will float, like oil. Anything more dense than water will sink, like rock.
Answer:
The anomalous expansion of water is an abnormal property of water whereby it expands instead of contracting when the temperature goes from 4o C to 0o C, and it becomes less dense. The density is maximum at 4 degree centigrade and decreases below that temperature as shown in graph.
Explanation:do you want me to explain it more??