All categories

3 years ago

A ball is launched at 40m/s. find its speed at the half way up point.

1 answer:

6 0

Ek - kinetic energy
v2 - unknown speed
v1 - 40 m/s (initial speed)
Ek=1/2 mv^2
Ek in half way up is 1/2 Ek (with another V)
So, Ek in the beginning is Ek1= 1/2 mv1^2
and in half way Ek2=1/2 mv2^2
Ek1=2*Ek2
1/2 mv1^2 = 2* 1/2 mv2^2
1/2 v1^2 = v2^2
1/2 40^2 = v2^2
800 = v2^2
v2 = sqrt (800) = 28,3 m/s

You might be interested in

Use the definition of scalar product, a overscript right-arrow endscripts times b overscript right-arrow endscripts = ab cos θ,

makkiz [27]

Answer: $\theta=cos^{-1}0.991=7.69^o$

The following vectors have been given: $\vec{a}=3.0\widehat{i}+3.0\widehat{j}+3.0\widehat{k}\\ \vec{b}=5.0\widehat{i}+7.0\widehat{j}+6.0\widehat{k}$

The angle between these two vectors can be found by:

$cos\theta=\frac{\vec{a}.\vec{b}}{||\vec{a}|| ||\vec{b}||}\\
||\vec{a}=\sqrt{a_x^2+a_y^2+a_z^2}$

$\vec{a}.\vec{b}=a_xb_x+a_yb_y+a_zb_z\\ \vec{a}.\vec{b}=3\times5+3\times7+3\times6=15+21+18=54$

$||\vec{a}||=\sqrt{3^2+3^2+3^2}=\sqrt{27}\\ ||\vec{b}||=\sqrt{5^2+7^2+6^2}=\sqrt{110}$

$cos\theta=\frac{54}{\sqrt{27}\times\sqrt{110}}\\=0.991\\ \Rightarrow \theta=cos^{-1}0.991=7.69^o$

7 0

3 years ago

How can you describe the path of the projectile motion?

tresset_1 [31]

Answer:

Projectile motion is a form of motion where an object moves in a bilaterally symmetrical+ parabolic path.

Explanation:

5 0

3 years ago

Read 2 more answers

How much work does it take to slide a box 37 meters along the ground by pulling it with a 217 N force at an angle of 19° from th

-Dominant- [34]

Answer:

W = 7591.56 J

Explanation:

given,

distance of the box, d = 37 m

Force for pulling the box, F = 217 N

angle of inclination with horizontal,θ = 19°

We know,

Work done is equal to product of force and the displacement.

W = F.d cos θ

W = 217 x 37 x cos 19°

W = 7591.56 J

Hence, the work done to pull the box is equal to W = 7591.56 J

8 0

3 years ago

Two force of 126N and 215N act on an object,calculate the magnitude and direction

yan [13]

The magnitude of the net force could be anything from 89N to 341N , and it could be acting in ANY direction.

To solve both mysteries we need to know the directions of the original two forces.

7 0

3 years ago

What is the fastest a car can go?

Brrunno [24]

Answer: hennessey venom f5 has gone 301mph. That is the fastest

Explanation:

6 0

3 years ago

Read 2 more answers