D

The fictional rocket ship Adventure is measured to be 65 m long by the ship's captain inside the rocket.When the rocket moves pa

kipiarov [429]

Answer:

1.04 s

Explanation:

The computation is shown below:

As we know that

t = t' × 1 ÷ (√(1 - (v/c)^2)

here

v = 0.5c

t = 1.20 -s

So,

1.20 = t' × 1 ÷ (√(1 - (0.5/c)^2)

1.20 = t' × 1 ÷ (√(1 - (0.5)^2)

1.20 = t' ÷ √0.75

1.20 = t' ÷ 0.866

t' = 0.866 × 1.20

= 1.04 s

The above formula should be applied

8 0

3 years ago

A 75 kg bobsled is pushed along a horizontal surface by two athletes. After the bobsled is pushed a distance of 4.5m starting fr

sergejj [24]

Answer:

The net force acting on the bobsled is 300 N.

Explanation:

Given:

Mass of the bobsled is, $m=75\ kg$

Displacement is, $d=4.5\ m$

Initial speed is, $u=0$ m/s

Final speed is, $v=6.0$ m/s

Net acceleration acting on the bobsled can be determined using the following Newton's equation of motion:

$v^2=u^2+2ad$

Plug in all the given values and solve for acceleration, $a$ .

$(6.0)^2=0+2a(4.5)\\36=9a\\a=\frac{36}{9}=4\ m/s^2$

Now, as per Newton's second law, net force is the product of mass and acceleration. So,

$F_{net}=ma\\F_{net}=75\times 4=300\ N$

Therefore, the net force acting on the bobsled is 300 N.

7 0

3 years ago

When jumping straight down, you can be seriously injured if you land stiff-legged. One way to avoid injury is to bend your knees

choli [55]

Answer:

a) F = 1.26 10⁵ N, b) F = 2.44 10³ N, c) F_net = 1.82 10³ N directed vertically upwards

Explanation:

For this exercise we must use the relationship between momentum and momentum

I = Δp

F t = p_f -p₀

a) It asks to find the force

as the man stops the final velocity is zero

F = 0 - p₀ / t

the speed is directed downwards which is why it is negative, therefore the result is positive

F = m v₀ / t

F = 63.5 7.89 / 3.99 10⁻³

F = 1.26 10⁵ N

b) in this case flex the knees giving a time of t = 0.205 s

F = 63.5 7.89 / 0.205

F = 2.44 10³ N

c) The net force is

F_net = Sum F

F_net = F - W

F_net = F - mg

let's calculate

F_net = 2.44 10³ - 63.5 9.8

F_net = 1.82 10³ N

since it is positive it is directed vertically upwards

6 0

3 years ago

A dragster completed a 402.3-(0.2500-mi) run in 5.023s. If the car had a constant acceleration, what was its acceleration and fi

Ray Of Light [21]

Answer:

v = 80.092 m/s

a = 15.945 m/s²

Explanation:

Given,

The distance completed by the dragster, d = 402.3 m

The time taken by the dragster to complete that distance is, t = 5.023 s

The initial velocity of the dragster, u = 0

The final velocity of the dragster, v = ?

The acceleration of the dragster, a = ?

The velocity of the body is given by the formula

v = d/t m/s

Substituting the above values inn the equation

v = 402.3 m / 5.023 s

= 80.092 m/s

So, the velocity of the dragster is, v = 80.092 m/s

The acceleration of the body is given by the formula

a = (v - u)/t m/s²

Substituting the above values in the equation

= (80.092 - 0) / 5.023

= 15.945 m/s²

Hence, the acceleration of the dragster is, a = 15.945 m/s²

6 0

3 years ago

The tools to distinguish the thickness of two objects of thickness of 1.92mm and the other with thickness of 1.93mm is ?

melomori [17]

Answer:

the instrument that gives this precision is the micrometer screw

Explanation:

The high precision measurements of small parts are the general vernier and the micrometer screw.

In these two instruments the same principle is used: there is a fixed rule and a mobile one that increases precision.

Let's analyze the absolute error or precision of each instrument

* For the vernier, the precision of the fixed rule is 1 mm and there are 20 divisions (the most common); therefore the precision of the instrument is

Δx = 1 mm / 20

Δx = 0.05 mm

* For the micrometer screw, the precision of the fida rule is 0.5 mm and the number of divisions is 50, therefore the precision of the screw is

Δx = 0.5mm / 50

Δx = 0.01 mm

consequently the instrument that gives this precision is the micrometer screw

8 0

3 years ago