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3 years ago

A 2kg ball is rolled along the floor for 0.8 m at a constant speed of 6 m/s. What is the work done by gravity?

Physics

2 answers:

riadik2000 [5.3K]3 years ago

3 0

=F×s×cosa=2×g×0,8×cos90°= 0

natulia [17]3 years ago

3 0

Answer:

work done=force×distance

=(2×10)×0.8

=16J

I hope this helps

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The height of a typical playground slide is about 1.8 m and it rises at an angle of 30 ∘ above the horizontal.

Salsk061 [2.6K]

Answer:

$5.94\ \text{m/s}$

$1.7$

$0.577$

Explanation:

g = Acceleration due to gravity = $9.81\ \text{m/s}^2$

$\theta$ = Angle of slope = $30^{\circ}$

v = Velocity of child at the bottom of the slide

$\mu_k$ = Coefficient of kinetic friction

$\mu_s$ = Coefficient of static friction

h = Height of slope = 1.8 m

The energy balance of the system is given by

$mgh=\dfrac{1}{2}mv^2\\\Rightarrow v=\sqrt{2gh}\\\Rightarrow v=\sqrt{2\times 9.81\times 1.8}\\\Rightarrow v=5.94\ \text{m/s}$

The speed of the child at the bottom of the slide is $5.94\ \text{m/s}$

Length of the slide is given by

$l=h\sin\theta\\\Rightarrow l=1.8\sin30^{\circ}\\\Rightarrow l=0.9\ \text{m}$

$v=\dfrac{1}{2}\times5.94\\\Rightarrow v=2.97\ \text{m/s}$

The force energy balance of the system is given by

$mgh=\dfrac{1}{2}mv^2+\mu_kmg\cos\theta l\\\Rightarrow \mu_k=\dfrac{gh-\dfrac{1}{2}v^2}{gl\cos\theta}\\\Rightarrow \mu_k=\dfrac{9.81\times 1.8-\dfrac{1}{2}\times 2.97^2}{9.81\times 0.9\cos30^{\circ}}\\\Rightarrow \mu_k=1.73$

The coefficient of kinetic friction is $1.7$ .

For static friction

$\mu_s\geq\tan30^{\circ}\\\Rightarrow \mu_s\geq0.577$

So, the minimum possible value for the coefficient of static friction is $0.577$ .

8 0

3 years ago

Atom in the ground state is said to be

koban [17]

Answer:

Ground-state atom

Explanation:

When an atom is not excited, it is in its ground-state, which we refer as "standard" or "normal" state.

(Hopefully that helped you!)

GOOD LUCK

Astrophysicist Dr. D

3 0

3 years ago

Mechanical energy is the sum of ________ energy and potential energy.apex

crimeas [40]

Mechanical energy is the sum of kinetic energy and potential energy

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3 years ago

A shopping mall has a length of 200 m and a width of 75 m. What is the area of the mall?

sweet [91]

To find the area, we just need to multiply the length by the width. 200 x 75 = 15,000. The mall has an area of 15,000 sq. feet.

6 0

3 years ago

List down atleast five activities where friction gave you an undesirable experience

Step2247 [10]

Answer:

Rug burn, Indian burn done to you by a friend, friction from the road causes your car to accelerate at a slower rate, The cylinder heads in an engine, When trying to move a heavy object across a rough surface

Explanation:

7 0

3 years ago

Read 2 more answers