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4 years ago

What is the cheetah's average speed for the first 3.11 s of its sprint? for the second 3.11 s of its sprint?

1 answer:

5 0

when you say a=4.02 i am going to acceleration in m/s^2. If the acceleration is 4.02 then you take the integral to find the speed. speed=4.02 t where t is time in seconds. [4.02(0)+4.02(3.11)]/2=6.2511 [4.02(3.11)+4.02(6.22)]/2=18.7533

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What's the answer to C??

Advocard [28]

With what? It won’t load.

4 0

3 years ago

A soft tennis ball is dropped onto a hard floor from a height of 1.95 m and rebounds to a height of 1.55 m. (Assume that the pos

Leokris [45]

Answer:

a) $v=6.19m/s$

b) $v=5.51m/s$

c) $a=3.3*10^{3}m/s^{2}$

d) $x=5.78*10^{-3}m$

Explanation:

h1=195m

h2=1.55

a) Velocity just before the ball strikes the floor:

Conservation of the energy law

$E_{o}=E_{f}$

$E_{o}=mgh_{1}$

$E_{f}=1/2*mv^{2}$

so:

$v=\sqrt{2gh_{1}}=\sqrt{2*9.81*1.95}=6.19m/s$

b) Velocity just after the ball leaves the floor:

$E_{o}=E_{f}$

$E_{o}=1/2*mv^{2}$

$E_{f}=mgh_{2}$

so:

$v=\sqrt{2gh_{2}}=\sqrt{2*9.81*1.55}=5.51m/s$

c) Relation between Impulse, I, and momentum, p:

$I=\Delta p\\ F*t=m(v_{f}-v{o})\\ (ma)*t=m(v_{f}-v{o})\\\\ a=\frac{ v_{f}-v{o}}{t}=\frac{ 5.51- (-6.19)}{3.5*10^{-3}}=3.3*10^{3}m/s^{2}$

d) The compression of the ball:

The time elapsed between the ball touching the ground and it is fully compressed, is half the time the ball is in contact with the ground.

$t_{2}=t/2=3.5/2=1.75ms$

Kinematics equation:

$x(t)=v_{o}t+1/2*a*t_{2}^{2}$

Vo is the velocity when the ball strike the floor, we found it at a) 6.19m/s.

a, is the acceleration found at c) but we should to use it with a negative sense, because its direction is negative a Vo, a=-3.3*10^3

So:

$x=6.19*1.75*10^{-3}-1/2*3.3*10^{3}*(1.75*10^{-3})^2=5.78*10^{-3}m$

5 0

3 years ago

if a 5-kg bowling ball is projected upward witha velocity of 2.0 m/s, then what is the recoil velocity of the Earth(mass=6.0×10^

vitfil [10]

by the concept of momentum conservation we can say

if net force on a system of mass is ZERO then its momentum will remain conserved

Here a ball is projected upwards so if we take Ball + Earth as a system then total momentum of the system will remain conserved

Initially when ball is on the surface of earth the system has zero momentum and hence we can say after throwing the ball momentum of earth + ball must be zero

now using same equation we can say

$P_{ball} + P_{earth} = 0$

$m_1v_1 + m_2v_2= 0$

given that

$m_1 = 5 kg$

$v_1 = 2 m/s$

$m_2 = 6 * 10^{24} kg$

from above equation velocity of earth will be

$v_2 = \frac{m_1 v_1}{m_2}$

$v_2 = \frac{5*2}{6 * 10^{24}}$

$v_2 = 1.67 * 10^{-24} m/s$

so above will be the recoil speed of earth

3 0

3 years ago

The weakest gravitational force caused by the Moon is called the __________, which is found at the point on Earth farthest from

skad [1K]

This is called Nadir.

4 0

2 years ago

A worker pushes a box across the floor to the right at a constant speed with a force of 25N. What

icang [17]

Answer:

Friction between the box and the floor is 25N to the left

Explanation:

There are two forces acting on the box along the horizontal direction:

- The force of push applied by the worker, in the forward direction, F

- The force of friction, $F_f$ , acting in the opposite direction (backward)

So the net force acting on the box is

$F_{net}=F-F_f$

According to Newton's second law of motion, the net force on an object is equal to the product between its mass (m) and its acceleration (a), so we can write:

$F_{net}=ma$