Answer:
the answer is A.) -1 * 10^3[N]
Explanation:
The solution consists of two steps, the first step is using the following kinematic equation:
![v=v_{i} +a*t\\where:\\v=final velocity [m/s]\\v_{i}=initial velocity [m/s]\\a=acceleration[m/^2]\\t=time[s]\\](https://tex.z-dn.net/?f=v%3Dv_%7Bi%7D%20%2Ba%2At%5C%5Cwhere%3A%5C%5Cv%3Dfinal%20velocity%20%5Bm%2Fs%5D%5C%5Cv_%7Bi%7D%3Dinitial%20velocity%20%5Bm%2Fs%5D%5C%5Ca%3Dacceleration%5Bm%2F%5E2%5D%5C%5Ct%3Dtime%5Bs%5D%5C%5C)
The initial velocity is 10 [m/s], and the final velocity is zero because the car stops in 0.5[s].
Replacing:
![0=10+a*(0.5)\\a=-20[m/s^2]](https://tex.z-dn.net/?f=0%3D10%2Ba%2A%280.5%29%5C%5Ca%3D-20%5Bm%2Fs%5E2%5D)
Now in the second part, we need to use the second law of Newton, this law relates the forces with the acceleration of a body.
In the moment when the car stops suddenly the driver will feel the force of the seatbelt acting in the opposite direction of the movement.
![F=m*a\\F=50[kg]*(-20[m/s^2])\\units\[kg]*[m/s^2]=[N]\\F=-1000[N] or -1*10^{3} [N]](https://tex.z-dn.net/?f=F%3Dm%2Aa%5C%5CF%3D50%5Bkg%5D%2A%28-20%5Bm%2Fs%5E2%5D%29%5C%5Cunits%5C%5Bkg%5D%2A%5Bm%2Fs%5E2%5D%3D%5BN%5D%5C%5CF%3D-1000%5BN%5D%20or%20-1%2A10%5E%7B3%7D%20%5BN%5D)
The minus sign means that the force is acting in the opposite direction of the movement.
Answer:
1. the principle of original horizontality
2. the principle of crosscutting relationships
3. the law of superposition
4. older
5. younger
Answer:
Explanation:
It is given that,
Speed of the projectile is 0.5 v. Let h is the height above the ground. Using the first equation of motion to find it.
Initial speed of the projectile is v and final speed is 0.5 v.
g is the acceleration due to gravity
Let h is the height above the ground. Using the second equation of motion as :
So, the height of the projectile above the ground is 
. Hence, this is the required solution.
The original width was 94.71 cm
<span>The area decreased 33.1% </span>
<span>The equation for the final size is </span>
<span>2X^2 = 1.2 m^2 </span>
<span>X^2 - 0.6 m^2 </span>
<span>X^2 = 10000 * .6 cm </span>
<span>X = 77.46 cm (this is the width) </span>
<span>The length is 2 * 77.46 = 154.92 cm </span>
<span>The original length was 154.92 + 34.5 = 189.42 cm </span>
<span>The original width was 189.42 / 2 = 94.71 cm </span>
<span>The original area was 94.71 * 189.92 = 17939.9 cm^2 </span>
<span>The new area is 79.46 * 154.92 = 12000.1 cm^2 </span>
<span>The difference between the original and current area is 17939.9 - 12000.1 = 5939.86 cm^2 </span>
<span>The percentage the area decreased is 5939.86 ' 17939.9 = 33.1%</span>
The process of flask becoming cold is due to endothermic reaction.
Answer: Option B
<u>Explanation:</u>
So two kinds of heat transfer can be possible in any chemical reaction. If the sample is considered as system and the sample container is considered as the surrounding, then heat transfer can occur between them.
If the heat is transferred from the surrounding to the system , then it is an endothermic reaction. And in those cases, the sample holder will be becoming colder. This is because the heat from the surrounding that is the container will be utilized to complete the reaction.
While when there is transfer of heat from the system to surrounding , it will be exothermic reaction and the beaker will be getting hot in this process. So in the present case, the container is becoming cold because of occurrence of endothermic process.
