Kinetic energy than parked
Answer:25.61 m/s
Explanation:
Given
truck is moving eastbound with a velocity of 16 m/s
Velocity of truck 
SUV is moving south with a velocity of 20 m/s
Velocity of SUV in vector form 
Velocity of truck relative to the SUV


Magnitude of relative velocity is

No. it is not good for people to live on Mars.
Answer:
3. 0.5 sec.
Explanation:
A bullet fired horizontally follows a projectile motion, which consists of two independent motions:
- A horizontal motion with constant speed
- A vertical motion with constant acceleration, g = 9.8 m/s^2, towards the ground
The time taken for the bullet to reach the ground can be calculated just by considering the vertical motion:

where y is the vertical position at time t, h is the initial height, and
is the initial vertical velocity of the bullet.
Since the bullet is fired horizontally,
. So the equation becomes

And the time that the bullet takes to reach the ground can be found by requiring y=0 and solving for t:

As we can see, in this equation there is no dependance on the initial speed of the bullet: therefore, if the bullet is fired still horizontally but with a different speed, it will still take the same time (0.5 s) to reach the ground.