Answer:
 x = 6.94 m
Explanation:
For this exercise we can find the speed at the bottom of the ramp using energy conservation
Starting point. Higher
             Em₀ = K + U = ½ m v₀² + m g h
Final point. Lower
              = K = ½ m v²
 = K = ½ m v²
             Em₀ = Em_{f}
             ½ m v₀² + m g h = ½ m v²
             v² = v₀² + 2 g h
              
Let's calculate
              v = √(1.23² + 2 9.8 1.69)
              v = 5.89 m / s
In the horizontal part we can use the relationship between work and the variation of kinetic energy
             W = ΔK
             -fr x = 0- ½ m v²  
                
Newton's second law
               N- W = 0
      
The equation for the friction is
                fr = μ N
                fr = μ m g
We replace
              μ m g x = ½ m v²
              x = v² / 2μ g
Let's calculate
             x = 5.89² / (2 0.255 9.8)
             x = 6.94 m
 
        
                    
             
        
        
        
Athletes of any kind can use technology to monitor things like their BMI (body mass index) or weight or anything of the sort to target what they need to work on to improve their health.
        
                    
             
        
        
        
Answer: the minimal force that you need to apply to move the bureau is F = 198.45N
Explanation:
If you want to move an object, you need to apply a force that is bigger than the force of the statical friction.
The force of statical friction can be written as.
Ff = k*N
where k is the coefficient of static friction, in this case, k = 0.45, and N is the normal force between the object and the surface.
In this case, the normal force is the weight of the bedroom bureau, this is:
N = m*g = 45kg*9.8m/s^2 = 441N
Then the force is:
Fr = 0.45*441N = 198.45N
This means that the minimal force that you need to apply to move the bureau is F = 198.45N
and after this point, the force of friction will work wit the kinetic coefficient of friction, that usually is smaller than the statical one.
 
        
             
        
        
        
Answer:
156.96 N
Explanation:
F=ma where m is the mass and a is acceleration
Substituting 16 Kg for m and 9.81 m/s2 for g then
F=16*9.81= 156.96 N
 
        
             
        
        
        
Try this solution (if it is possible, check it in other sources):
1. for m_Tarzan=75kg., initial_height=4m., end_height=0 m. and g=10 N/kg. Energy is:

2. The same value of Energy is applied for m_Tarzan+Jane=75+50=125 kg.:

3. According to the formula of the Speed:
Speed=sqrt(6000/125)=sqrt(48)=4sqrt(3)≈4*1.71=6.84 (m/s)
Answer: 6.84 (m. per sec.)