Answer: d. 8.25 m/s
Explanation:
We are given that Current= 5 m/s in j direction
Velocity= 8 m/s i + 3 m/s j
Now, we have to find Jada's speed with respect to the water.
First we find Jada's velocity with respect to water
v= (8 i + 3 j) - (5 j)
v= 8i - 2 j
To find the speed, we take the magnitude of this velocity vector we have
|v|= 
|v|=
= 8.246 m/s
which comes out to be around = 8.25 m/s
So option d is correct.
Answer:
A, the energy an object has due to its motion.
Explanation:
Kinetic energy is the energy created by motion.
To solve this problem we will apply the linear motion kinematic equations. From the definition of the final velocity, as the sum between the initial velocity and the product between the acceleration (gravity) by time, we will find the final velocity. From the second law of kinematics, we will find the vertical position traveled.

Here,
v = Final velocity
= Initial velocity
g = Acceleration due to gravity
t = Time
At t = 4s, v = -30m/s (Downward)
Therefore the initial velocity will be


Now the position can be calculated as,

When it has the ground, y=0 and the time is t=4s,


Therefore the cliff was initially to 41.6m from the ground
Answer: m = 0.4 kg
Explanation: Momentum is the product of mass and velocity also expressed in this equation:
p = m x v
Derive to find m
m = p / v
= 10 kg•m/s / 25 m/s
= 0.4 kg
They all stay the same regardless