Answer: Normal force, N = 141.64 Newton
Explanation:
All the forces acting on the system and described in free body diagram are:
1) gravitational pull in downward direction
2) Normal force in upward direction
3) External force of 40 N acting at an angle of 37° with the horizontal can be resolved in two rectangular components:
i) F Cos 37° along the horizontal plane in forward direction and
ii) F Sin 37° along the vertical plane in downward direction
Applying the Newton's second law, net forces in the vertical plane are:
Net force, f = N - (mg + F Sin 37°)
As there is no acceleration in the vertical plane hence, net force f = 0.
So,
N - (mg + F Sin 37°) = 0
Adding (mg + F Sin 37°) both the sides in above equation, we get
N = mg + F Sin 37°
N = 12
9.8 + 40
0.601 because (Sin 37° = 0.601)
N = 117.6 + 24.04
N = 141.64 Newton
Answer:160.88 m
Explanation:
Given
Distance Between two person is 100
i.e. 
Let W be the width of River
From First Triangle

From Second Triangle





Answer:D
Explanation:
Given
mass of object 
Distance traveled 
velocity acquired 
conserving Energy at the moment when object start falling and when it gains 12 m/s velocity
Initial Energy
Final Energy

where
is friction work if any


Since Friction is Present therefore it is a case of Open system and net external Force is zero
An open system is a system where exchange of energy and mass is allowed and Friction is acting on the object shows that system is Open .
Answer:
0.0367
Explanation:
The loss in kinetic energy results into work done by friction.
Since kinetic energy is given by
KE=0.5mv^{2}
Work done by friction is given as
W= umgd
Where m is the mass of suitacase, v is velocity of the suitcase, g is acceleration due to gravity, d is perpendicular distance where force is applied and u is coefficient of kinetic friction.
Making u the subject of the formula then we deduce that

Substituting v with 1.2 m/s, d with 2m and taking g as 9.81 m/s2 then

Therefore, the coefficient of kinetic friction is approximately 0.0367
Answer:
30.93 m/s
Explanation:
Given that, the speed of stolen car is,

As policeman start chasing the stolen car after 60 seconds.
Now suppose the speed of policeman car is, 
The policeman catches the stolen car at a distance of,

Now the distance covered by the policeman in time t is 
And the distane cover by the thief in stolen car in time(t+60s) is
.
And these distances are equal and they are equal to 60000 m.
Therefore,

Therfore,

Now use this value to solve for minimum speed of policeman's car.

Therefore minimum speed of policeman's car is 30.93 m/s.