To find 
we need to use vector addition and use the x and y components. First we subtract vector 2 from vector 5 which results in a vector with a length of 3 pointing directly east, then we use the distance formula to find the length of the net force 
which gives 
. We now have a magnitude but we also need a direction, since vector 4 and vector 5 are perpendicular. Using 
where tan^-1(y/x) we get an angle of 53 degrees. The resultant force vector is 5 distance with an angle of 53 degrees north east.
equal and opposite reaction.
Answer:
b) The downward force of gravity
Explanation:
The gravity force has the biggest influence on the deceleration of the ball because no matter how much force you applied on the ball, it will eventually go down again, according to newton's second law:
right after you throw the ball, only the force exerted by the gravity will affect the ball (neglecting air resistance):
so the object will eventually be going down again.
Answer:
c)by a factor of four
Explanation:
The total energy of a simple harmonic oscillator is given by
where
k is the spring constant of the oscillator
A is the amplitude of the motion
In this problem, the amplitude of the oscillator is doubled, so
A' = 2A
Therefore, the new total energy is
So, the total energy increases by a factor 4.
Consider the upward direction of motion as positive and downward direction of motion as negative.
a = acceleration due to gravity in downward direction = - 9.8 
v₀ = initial velocity of rock in upward direction = ?
v = final velocity of rock at the highest point = 0 
t = time to reach the maximum height = 4.2 sec
Using the kinematics equation
v = v₀ + a t
inserting the values
0 = v₀ + (- 9.8) (4.2)
v₀ = 41.2
