Answer:
a) 
b) the motorcycle travels 155 m
Explanation:
Let
, then consider the equation of motion for the motorcycle (accelerated) and for the car (non accelerated):

where:
is the speed of the motorcycle at time 2
is the velocity of the car (constant)
is the velocity of the car and the motorcycle at time 1
d is the distance between the car and the motorcycle at time 1
x is the distance traveled by the car between time 1 and time 2
Solving the system of equations:
![\left[\begin{array}{cc}car&motorcycle\\x=v_0\Delta{t}&x+d=(\frac{v_0+v_{m2}}{2}}) \Delta{t}\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7Dcar%26motorcycle%5C%5Cx%3Dv_0%5CDelta%7Bt%7D%26x%2Bd%3D%28%5Cfrac%7Bv_0%2Bv_%7Bm2%7D%7D%7B2%7D%7D%29%20%5CDelta%7Bt%7D%5Cend%7Barray%7D%5Cright%5D)

For the second part, we need to calculate x+d, so you can use the equation of the car to calculate x:

Answer:
Let the weight of the ruler be X.
Now X acts in the middle, so we have 55-50 = 50cm
Since left hand movement= right hand movement
X(55-50)=90(95-55)
5X= 90×40
X=320cm
Hence the weight of the ruler is 320g
Explanation:
Answer:
Jupiter
Explanation:
Since the mass of Jupiter is the greatest from the given choices, it will exert the most force on any object orbiting 100km above its surface.
This is compliance with the Newton's law of universal gravitation which states that "the force of attraction between two bodies is directly proportional to the magnitude of their masses and inversely proportional to the distances between them".
- Therefore, the more the masses of two bodies, the higher the gravitational attraction
- Since the distance is the same, the planet with the greater mass will exert the most force on the satellite.
Answer: A,B, and E
Explanation: Just checked I got them right:)