Explanation​:
For any force, the direction is an essential aspect of the quantity. All other options here are scalar quantities.

Explanation​:
In order for the plane to travel from A to $B$, the resultant vector of the sum of the wind vector and the vector of the orientation of the plane must point in the same direction as the vector from A to $B$, as shown in the diagram below. For any of the other choices, the resultant will not be in the direction A to $B$.

Explanation​:
Weight always acts vertically downwards

Normal reaction force is always normal (perpendicular) to the surface

In order to remain at rest, friction must act up the incline in order to keep the block from sliding down the incline under the action of the component of weight acting down the incline.

In diagram B, friction is acting down the incline. This will result in an acceleration down the incline.

In diagram C, the normal reaction is acting opposite to the weight whereas normal reaction must always be perpendicular to the contact surface.

In diagram D, weight is shown to act at an angle to the vertical, whereas weight always acts vertically downwards.

Explanation​:
The motion of the car here is in the direction of the sum of the two forces vectors from $X$ and $Y$.
The only vector that will add to vector $X$ to produce a net force vector to the right is one in the direction of C.

Explanation​:
The change in momentum and impulse applied to the ball are equal, because the impulse is defined as the change in momentum. Increasing one is the same as increasing the other and vice-versa. The slower rebound speed of the second ball causes a decrease in the magnitude of the impulse since the change in momentum is smaller if the final speed $v$ is smaller.

$I=\Delta p=m(v--u)=m(v+u)$

Explanation​:

Energy transferred to thermal energy will be the work done by the frictional force.

Frictional force = μFN=μmg (where FN=mg)

Work = Fd=μmgd

Explanation​:
I is correct.
The accelerating force is always perpendicular to the direction of motion, therefore no work is done.
$)$, and $\theta$ is always 90$°$.
Also, W=ΔEk and the speed of the object is constant so there is no change in kinetic energy.

II is incorrect.
Because velocity is a vector quantity and the direction is constantly changing, velocity is not constant.

III is correct.
Because velocity is constantly changing, the object is always accelerating.

Explanation‾Explanation​:
Displacement is the area under the graph of velocity-time. Breaking the shape into several areas up to time 7s:

Explanation​:
The arrows that turn downwards represent energy degradation. he widths are proportional to the amount of energy in that stage. The widest of these is B

Explanation​:

sin 35o=vy/2​​

Therefore vy=2 sin(35o)

Explanation​:

Muons have a very short lifetime to reach the earth's surface from the upper atmosphere. But they are abundant on the Earth’s surface. This observation can be explained in two ways: Due to time dilation, from the perspective of muons, time passes more slowly, allowing them to cover more distance during their short lifetime. Alternatively, due to length contraction, the distance that muons need to travel to reach the Earth appears shorter from their perspective.

Explanation​:
B is the only diagram that shows weight and tension, with the vertical component of tension equal in magnitude to the weight vector. Upwards and horizontal forces on the mass are only provided by the tension force.

Explanation​:
For option A, the gradient of the line connecting the starting and ending velocities gives the average acceleration.
For option B, x-intercept represents the time of when velocity is zero, therefore is incorrect.
For option C, y-intercept represents the velocity when the time is zero, therefore is incorrect.
For option D, area under the graph is the displacement, which is the correct answer.

Explanation​:

The area underneath of the force-time graph gives the change in momentum of the box. Since the area increases with time at a constant rate, the momentum should increase at a constant rate. The only graph that satisfies this condition is the graph in A.

Therefore, the answer is A.

Alternatively, the impulse equation gives Δp=FΔt .

As $F$ is a constant, Δp is directly proportional to $t$ and a straight line through the origin is expected.

Explanation​:
The centripetal force on an object undergoing uniform circular motion is always towards the centre of the circle therefore the direction is different at the different locations. The magnitude of centripetal force is dependent on the radius of the circular path and the speed of the object. Since both of them are the same at both locations, the magnitude of centripetal force is constant throughout the motion. Therefore, the answer is C.

Explanation​:
Impulse = change in momentum = $Ft$

So the magnitude of the change in momentum = (5.1×10^3)(3.0) = 15300 $Ns$

All responses match this quantity but the number of significant figures needs to be considered. As both of the values used in the calculation have two significant figures, there should be two significant figures in the answer.

In the answer $15000Ns$, the number of significant figures is unclear. It could be 2, 3, 4 or 5. The response $15kNs$ clearly has two significant figures, so it is the best answer.

Explanation​:
The centripetal force will act towards the centre of the circular path. In this case, it is the horizontal component of the lifting force.

This is given by $Lsin\theta$ 

Explanation​:
The rocket is not a closed system. The reaction force from ejecting hot gas will increasingly accelerate the rocket, hence D

Explanation​:

There are two forces acting on the pilot which are the gravitational force (weight) and the normal force of the pilot's chair.

The normal force always acts from the chair onto the person. At the top of the loop, this will act vertically downwards.

The weight is always vertically downwards.