Answer:
25.2 km east
Explanation:
The relationship between velocity and displacement is given by:

where
v is the velocity
d is the displacement
t is the time
In this problem, we have:
east is Rebecca's velocity
is the time taken
Re-arranging the equation, we can find Rebecca's displacement:

and the direction is same as velocity (east)
Answer:
Magnitude 900m/s, direction 12.8° respect to the velocity of the first asteroid.
Explanation:
This is a perfectly inelastic collision, because the two asteroids stick together at the end. That means that the kinetic energy doesn't conserves, but the linear momentum does. But, since the velocities of the asteroids have different directions, we have to break down them in components. For convenience, we will take the direction of the first asteroid as x-axis, and its perpendicular direction (in the plane of the two velocity vectors) as y-axis. So, we have that:

And, since
, we get:

Solving for v_fx and v_fy, and calculating their values, we get:

Now, the final speed can be calculated using the Pythagorean Theorem:

And the direction
can be obtained using trigonometry:

That means that the final velocity of the two asteroids has a magnitude of 900m/s and a direction of 12.8° with respect to the velocity of the first asteroid.
The answer should be C. In this question
Answer:
710kg
Explanation:
Given parameters:
Weight of race car = 6958N
Unknown:
Mass of the race car = ?
Solution:
The weight of a body is the force of gravity acting on that body. It is mathematically expressed as:
Weight = mass x acceleration due to gravity
Acceleration due to gravity = 9.8m/s²
6958 = mass x 9.8
mass = 710kg