In order to overcome an object’s inertia (resistance to change), it must be acted upon by an unbalanced force, so the answer to the problem is letter C.
        
                    
             
        
        
        
Answer:
Yes
Explanation:
The core of an electromagnet serves to stabilize the magnetic field created by the wire. The thicker the core, the more metal there is to amplify the current. Therefore, a thicker core does make an electromagnet stronger. Hope this helps!
 
        
             
        
        
        
Answer:
Explanation:
Maximum force of friction possible = μmg
= .65 x 3.8 x 9.8 
= 24.2 N 
u = 72 x 1000 / 60 x 60
= 20 m /s 
v² = u² - 2as 
a = 20 x 20 / (2 x 30)
= 6.67 m / s²
force acting on it 
= 3.8 x 6.67
= 25.346 N 
Friction force possible is less . 
So friction will not be able to prevent its slippage 
It will slip off . 
 
        
             
        
        
        
Answer:
Explanation:
The vehicle is experiencing a large force created by the concrete wall.
Equation
vf^2 = vi^2 + 2*a * d
Givens
vf = 0   The car eventually does stop.
vi = 72 km/hr * [ 1000 m/  km] * [1 hour / 3600 seconds]
vi = 20 meters / second
a = ?
m = 850 kg
Solution
vf^2 = vi^2 + 2a*d
0 = 20 m/s + 2* 2 *a
-20 m/s = 4a
-20/4 =   a
a = - 5 m/s^2   The minus sign tells you the vehicle is slowing down. It sure should be.
Force = m * a
F = - 850 * (-5)
F =  - 4250 N
The car provides a 4250 N force on it going east to west and a 4250 N force going from west to east provided by the concrete wall.