Machines makes work easier by increasing the amount of force that is applied, and changing the direction in which the force is applied !! Hope it helped (p.s. I had this same question)
<span>B. It stays the same</span>
Answer:
Explanation:
The acceleration of gravity is 9.8m/s^2.
So to calculate the time it will take to make the ball stop(which btw means the ball now reach its greatest height), use the formula V1=V0+at. V1 is the final velocity(which is 0), V0 is the starting velocity(which is 30m/s), and the a(cceleration) is 9.8m/s^2.
(You can ignore the fact "at" is -30 instead 30, it's because the directions two velocity travel are opposite. )
We can now know the time it takes to make the ball stop just by the gravitational force is about 3 sec.
Use another formula S=1/2at^2, to find out the S(height) is 1/2*9.8*3^2=44.1, which is approximately D.45m .
Answer: C. 1.64 x 10-3 m/s2
<u>Answer:</u>
Prior to exercise, a proper warm-up of 10-15 minutes is extremely important to avoid injuries.
- Don't go too hard in the beginning and boost your activity level slowly. A good indication of a proper warm-up is that you feel sweat on your body parts.
- Don't overstretch right in the beginning as it can cause sore in your muscles and joints or stress fractures.
- Take a break if you feel sick or fatigues and use other drinks along with water to replace electrolytes and body fluids.
