Pls help i am in8th grade k12

a basketball (hollow sphere) starts from rest and rolls down a hill without slipping. the hill is 70 meter high. total mechanica

blondinia [14]

The linear speed of the basketball at the bottom in m/s is 37.41 m/s.

The mechanical energy basket ball is conserved and the basket ball starts from rest. and roll down a hill of height 70m.

If mechanical energy is conserved,

Potential energy at top + kinetic energy at top = potential energy at bottom + kinetic energy at bottom.

At bottom, there is no potential energy, and at top, there is no kinetic energy.

Potential energy at top = kinetic energy at bottom.

Mgh = 1/2Mv²

M is the mass of the basketball,

v is the linear speed at the bottom,

h is the height of the ball.

Putting values,

v = √(2gh)

v = √(2x10x70)

v = 37.41m/s.

The speed of the basketball at the bottom is 37.41 /s.

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6 0

1 year ago

A bottle dropped from a balloon reaches the ground in 20 s. determine the height of the balloon if (a) it was at rest in the air

romanna [79]

<span>a) 1960 m b) 960 m Assumptions. 1. Ignore air resistance. 2. Gravity is 9.80 m/s^2 For the situation where the balloon was stationary, the equation for the distance the bottle fell is d = 1/2 AT^2 d = 1/2 9.80 m/s^2 (20s)^2 d = 4.9 m/s^2 * 400 s^2 d = 4.9 * 400 m d = 1960 m For situation b, the equation is quite similar except we need to account for the initial velocity of the bottle. We can either assume that the acceleration for gravity is negative, or that the initial velocity is negative. We just need to make certain that the two effects (falling due to acceleration from gravity) and (climbing due to initial acceleration) counteract each other. So the formula becomes d = 1/2 9.80 m/s^2 (20s)^2 - 50 m/s * T d = 1/2 9.80 m/s^2 (20s)^2 - 50m/s *20s d = 4.9 m/s^2 * 400 s^2 - 1000 m d = 4.9 * 400 m - 1000 m d = 1960 m - 1000 m d = 960 m</span>

6 0

4 years ago

Flying plane

Fittoniya [83]

Answer

a. These are objects in motion that have kinetic energy.

Explanation:

5 0

4 years ago

Read 2 more answers

PLEASE HELP ASAP I WILL GIVE BRAINIEST

8090 [49]

Answer:

11. 3

12. 2

13. 2

14. 1

15. 3

16. 3

17. 2

18. 2

19. 2

Explanation:

Hope This Helps

Brainlest Plz

5 0

3 years ago

Read 2 more answers

Vector A has a magnitude of 8.0 m and points east, vector B has a magnitude of 6.0 m and points north and vector C has a magnitu

sineoko [7]

Answer:

The answer is E) 6.7m at an angle 63° north of east

Explanation:

We begin by writing out our given vectors A,B and C in their respective rectangular Cartesian coordinate form. which are given as A=8i, B=6j and C= -5j (negative because it points towards west which is towards the left which is taken as the negative direction).Now we simply add all three to obtain our final vector given by,

$V=A+B+C\\V=8i + 6j - 5i\\V=3i + 6j$

In the last step we just added the like components. Now we will have to calculate the magnitude and angle of V(with respect of the east direction), which is given by,

$|V| = \sqrt{3^2 + 6^2} =6.7m\\\\\alpha =tan^{-1} (6/3)=tan^{-1} (2) = 63.4$

the angle alpha is always calculated with respect to the horizontal positive axis, and since both components of the vector are positive the vector lies in the first quadrant. Hence the 63° angle north of east is justified. The term north of east means the angle formed in moving from east towards the north that is from the positive horizontal axis to the positive vertical axis.

8 0

4 years ago