Nuclear reactions have many useful applications, but they also have harmful biological effects.
1 answer:
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Answer:
6 m/s
Explanation:
To determine the change in speed of the object, we just need to determine its speed at t = 30 s and at t = 20 s, and then calculate the difference.
The speed at t = 30 is:
v = 6 m/s
While the speed at t = 20 s is:
u = 0
Therefore, the change in speed is:
Answer:
a.18.5 m/s
b.1.98 s
Explanation:
We are given that
a.Let be the initial velocity of the ball.
Distance,x=30 m
Height,h=1.8 m
Substitute the values
Initial velocity of the ball=18.5 m/s
b.Substitute the value then we get
t=1.98 s
Hence, the time for the ball to reach the target=1.98 s
Answer:
0.074m/s
Explanation:
We need the formula for conservation of momentum in a collision, this equation is given by,
Where,
= mass of ball
= mass of the person
= Velocity of ball before collision
= Velocity of the person before collision
= velocity of ball afer collision
= velocity of the person after collision
We know that after the collision, as the person as the ball have both the same velocity, then,
Re-arrenge to find ,
Our values are,
= 0.425kg
= 12m/s
= 68.5kg
= 0m/s
Substituting,
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<em>The speed of the person would be 0.074m/s after the collision between him/her and the ball</em>