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.
The hotter an object is, the more kinetic energy it has, but i'm not sure what is the exact word missing??
Answer:
The value of tangential acceleration
40 
The value of radial acceleration 
Explanation:
Angular acceleration = 50 
Radius of the disk = 0.8 m
Angular velocity = 10 
We know that tangential acceleration is given by the formula

Where r = radius of the disk
= angular acceleration
⇒
0.8 × 50
⇒
40 
This is the value of tangential acceleration.
Radial acceleration is given by

Where V = velocity of the disk = r 
⇒ V = 0.8 × 10
⇒ V = 8 
Radial acceleration


This is the value of radial acceleration.