Answer:
The acceleration of the object is -69.78 m/s²
Explanation:
Given;
postion of the particle: 

The velocity of the particle is calculated as the change in the position of the  particle with time;

Acceleration is the change in velocity with time;

 
        
             
        
        
        
Answer: 90 kgm/s
Explanation:
The momentum (linear momentum)  is given by the following equation:
 is given by the following equation:
 
 
Where:
 is the mass of the skater
 is the mass of the skater
 is the velocity
 is the velocity 
In this situation the skater has two values of momentum:
Initial momentum: 
Final momentum: 
Where:


So, if we want to calculate the difference in the magnitude of the skater's momentum, we have to write the following equation(assuming the mass of the skater remains constant):
 
 
 
 
 
 
Finally:
 
 
 
        
                    
             
        
        
        
Answer:
 increasing the temperature of the rod
Explanation:
Sound wave is a longitudinal wave and its speed in a solid rod is given by the formula

here we know that
Y = young's modulus
 = density of the medium
 = density of the medium
so as we increase the temperature of rod the density of the rod will decrease while the elasticity will remain same
So on increasing the temperature we can say that speed will increase due to decrease in the density
 
        
             
        
        
        
Answer:
3) C 
4 D
5) C
Explanation:
3) given that 
Initial distance of the screen = 100cm
Initial area = 150 cm^2
 Final distance = 200 cm
The intensity of light is inversely proportional to the square of the distance. That is 
Intensity of light I = 1/d2
And also I = P/A
1/d^2 = P/A
P = A/d^2
P1 = P2
150/100 = A/200
1.5 = A/200
A = 1.5 × 200
A = 300 cm^2
4.) Light is projected onto a screen 75.0 cm from a light source. The light intensity = 4436 lux 
If the screen is moved from 75.0 cm to 150. cm, the light sensor reading will be
Using inverse square law
I = 1/d^2
I×d^2 = constant. Therefore, 
4436 × 75^2 = I × 150^2
I = 24952500/22500
I = 1109 lux
5.) We can express the relationship between luminosity, brightness, and distance with a simple formula.
 As we tilt the serene the area of light decreases and makes the light more concentrated.
 
        
             
        
        
        
Answer:
True. 
Explanation:
A nutritionist must be licenced in order to be certified to practice in the United States.