Answer:

Explanation:
<u>Motion With Constant Acceleration
</u>
It's a type of motion in which the velocity of an object changes uniformly in time.
The formula to calculate the change of velocities is:

Where:
a = acceleration
vo = initial speed
vf = final speed
t = time
The roller coaster moves from vo=6 m/s to vf=70 m/s in t=4 seconds. To calculate the acceleration, solve for a:



This question is based on the fundamental assumption of vector direction.
A vector is a physical quantity which has magnitude as well direction for its complete specification.
The magnitude of a physical quantity is simply a numerical number .Hence it can not be negative.
A negative vector is a vector which comes into existence when it is opposite to our assumed direction with respect to any other vector. For instance, the vector is taken positive if it is along + X axis and negative if it is along - X axis.
As per the first option it is given that a vector is negative if its magnitude is greater than 1. It is not correct as magnitude play no role in it.
The second option tells that the magnitude of the vector is less than 1. Magnitude can not be negative. So this is also wrong.
Third one tells that a vector is negative if its displacement is along north. It does not give any detail information about the negativity of a vector.
In a general sense we assume that vertically downward motion is negative and vertically upward is positive. In case of a falling object the motion is vertically downward. So the velocity of that object is negative .
So last option is partially correct as the vector can be negative depending on our choice of co-ordinate system.
Answer:
the thermistor temperature = 
Explanation:
Given that:
A thermistor is placed in a 100 °C environment and its resistance measured as 20,000 Ω.
i.e Temperature
Resistance of the thermistor
20,000 ohms
Material constant
= 3650
Resistance of the thermistor
= 500 ohms
Using the equation :


Taking log of both sides





Replacing our values into the above equation :






Thus, the thermistor temperature = 
Answer:
If the voltage is increased then the electric field is higher, and electron velocity (average) is proportional to this field. Then you have an increase in speed. And current is total charge passing per time unit, so current is proportional to velocity value of charge (and to voltage in resistors and wire).
Explanation: