Answer
4.8 N
If the box is moving with a constant velocity, then we can say that the system is in equilibrium. This is because if the external force (F->) was greater than other forces the box would be accelerating. This tells us that this force (F->) is just enough to overcome friction and so it must be equal to 4.8 N.
The normal force has no effect to the horizontal velocities or forces. It is equal to -Weight. That is -74 N. The negative sign shows that the force is in opposite direction.
This question is based on the fundamental assumption of vector direction.
A vector is a physical quantity which has magnitude as well direction for its complete specification.
The magnitude of a physical quantity is simply a numerical number .Hence it can not be negative.
A negative vector is a vector which comes into existence when it is opposite to our assumed direction with respect to any other vector. For instance, the vector is taken positive if it is along + X axis and negative if it is along - X axis.
As per the first option it is given that a vector is negative if its magnitude is greater than 1. It is not correct as magnitude play no role in it.
The second option tells that the magnitude of the vector is less than 1. Magnitude can not be negative. So this is also wrong.
Third one tells that a vector is negative if its displacement is along north. It does not give any detail information about the negativity of a vector.
In a general sense we assume that vertically downward motion is negative and vertically upward is positive. In case of a falling object the motion is vertically downward. So the velocity of that object is negative .
So last option is partially correct as the vector can be negative depending on our choice of co-ordinate system.
We know,
V= f× wavelength
10.5= f×0.15
f=10.5/0.15
f= 70 Hz
<em>Resultant angle; θ = 25.59° </em>
This question is dealing with bearings and distance.
We are told that from point A, the camel walks 20 km at 15° in the south of east direction.
Thus, d_s,e = 20 km
Resolving along the horizontal east direction gives; d_e = 20 cos 15
d_e = 19.32 km
Also, resolving along the vertical south direction gives; d_s = 20 sin 15
d_s = 5.18 km
Net vertical distance; d_vert = 8km - 5.18km = 2.72 km
Net horizontal distance; d_hor = 25km - 19.32 km = 5.68 km
Now, the resultant angle is given by;
tan θ = d_vert/d_hor
tan θ = 2.72/5.68
tan θ = 0.4789
θ = tan^(-1) 0.4789
θ = 25.59°
Read more at; brainly.com/question/22518031
