Ask question

Ask question

All categories

3 years ago

11

a motorcycle is trying to leap across the canyon by driving horizontally off a cliff 38 m/s. Ignoring air resistance, find the s

peed with which the cycle strikes the ground on the other side

1 answer:

vaieri [72.5K]3 years ago

3 0

Answer:

46.15m/s

Explanation:

We are given that

Initial speed,u=38 m/s

Height of cliff,h=70 m

We have to find the speed with which the cycle strikes the ground at a height 35 m on the other side.

h'=35 m

Using conservation law of energy

$\frac{1}{2}mu^2+mgh=\frac{1}{2}mv^2+mgh'$

$\frac{1}{2}u^2+gh=\frac{1}{2}v^2+gh'$

Where $g=9.8m/s^2$

Substitute the values

$\frac{1}{2}(38)^2+9.8\times 70=\frac{1}{2}v^2+9.8\times 35$

$\frac{1}{2}v^2=\frac{1}{2}(38)^2+9.8\times 70-9.8\times 35=1065$

$v=\sqrt{2\times 1065}$

$v=46.15m/s$

You might be interested in

An energy pyramid illustrates that energy in the form of _____ is lost to the surroundings as it's passed from one organism to t

Dima020 [189]

The answer is metabolic heat.

<span>Organisms from the higher trophic levels consume organisms from the lower trophic level and during that process, energy is lost as metabolic heat. Primary producers (plants) contain the greatest amount of energy originally from the sunlight. The next trophic level belongs to primary consumers that consume primary producers. During consumption, energy is lost. Similarly, secondary consumers eat primary consumers and energy is lost again. The highest trophic level is tertiary consumers that contains the least amount of energy.</span>

5 0

3 years ago

A vertical straight conductor X of length 0.5m is held along the positive X-axis and situated in a uniform horizontal magnetic f

k0ka [10]

Answer:

i. 0.2 N ii. 30°

Explanation:

(i) Calculate the magnitude and direction of force on X, when a current of 4A is passed through it.

The magnetic force F = BILsinФ where B = magnetic field strength = 0.1 T, I = current = 4 A and L= length of conductor = 0.5 m. Since the conductor X of length 0.5m is held along the positive X-axis and situated in a uniform horizontal magnetic field of 0.1T which is pointing towards the positive Y-axis, both B and L are perpendicular to each other. So, Ф = 90°

So, F = BILsinФ

F = 0.1 T × 4 A ×0.5 m × sin90°

F = 0.1 T × 4 A ×0.5 m × 1

F = 0.2 N

(ii) Through what angle must X be turned in a vertical plane so that the force on X is halved

If F' = BILsinФ' where Ф'=the new angle, and BIL = F

F'/F = sinФ'

Since F'/F = 1/2

sinФ' = 1/2

Ф' = sin⁻¹(1/2) = 30°

4 0

3 years ago

A wire of cross-sectional area 5.00 106 m2 has a resistance of 1.75 O. What is the resistance of a wire of the same material and

MakcuM [25]

Answer:

the resistance of the second wire is 1 ohm.

Explanation:

Given;

cross sectional area of the first wire, A₁ = 5.00 x 10⁶ m²

resistance of the first wire, R₁ = 1.75 ohms

cross sectional area of the second wire, A₂ = 8.75 x 10⁶ m²

resistance of the second wire, R₂ = ?

The resistance of a wire is given as;

R ∝ $\frac{L}{A}$

Since the length of the two wires is constant

R₁A₁ = R₂A₂

$R_2 = \frac{R_1A_1}{A_2} \\\\R_2 = \frac{1.75\ \times \ 5.00\times 10^6}{8.75\times 10^6} \\\\R_2 = 1 \ ohm$

Therefore, the resistance of the second wire is 1 ohm.

6 0

3 years ago

A driver enters a one-lane tunnel at 34.4 m/s. The driver then observes a slow-moving van 154 m ahead travelling (in the same di

navik [9.2K]

Answer:

Ans. B) 22 m/s (the closest to what I have which was 20.16 m/s)

Explanation:

Hi, well, first, we have to find the equations for both, the driver and the van. The first one is moving with constant acceleration (a=-2m/s^2) and the van has no acceletation. Let´s write down both formulas so we can solve this problem.

$X(van)=5.65t+154$

$X(driver)=34.4t+\frac{(-2)t^{2} }{2}$

or by rearanging the drivers equation.

$X(driver)=34.4t+t^{2}$

Now that we have this, let´s equal both equations so we can tell the moment in which both cars crashed.

$X(van)=X(driver)$

$5.65t+154=34.4t-t^{2}$

$0=t^{2} -(34.4-5.65)t+154$ $0=t^{2} -28.75t+154$

To solve this equation we use the following formulas

$t=\frac{-b +\sqrt{b^{2}-4ac } }{2a}$

$t=\frac{-b +\sqrt{b^{2}-4ac } }{2a}$

Where a=1; b=-28.75; c=154

So we get:

$t=\frac{28.75 +\sqrt{(-28.75)^{2}-4(1)(154) } }{2(1)}=21.63s$ $t=\frac{28.75 -\sqrt{(-28.75)^{2}-4(1)(154) } }{2(1)}=7.12s$

At this point, both answers could seem possible, but let´s find the speed of the driver and see if one of them seems ilogic.

$V(driver)=V_{0} +at$ }

$V(driver)=34.4\frac{m}{s} -2\frac{m}{s^{2} } *(7.12s)=20.16\frac{m}{s}$ $V(driver)=34.4\frac{m}{s} -2\frac{m}{s^{2} } *(21.63s)=-8.86\frac{m}{s}$

This means that 21.63s will outcome into a negative speed, for that reason we will not use the value of 21.63s, we use 7.12s and if so, the speed of the driver when he/she hits the van is 20.16m/s, which is closer to answer A).

Best of luck

8 0

3 years ago

The battery is made up of three 1.5 V cells.

IrinaVladis [17]

Answer: 4.5 V

Explanation:

Given

The voltage of each cell is 1.5 V

If they are connected end to end their potential added to give a higher potential i.e. 1.5+1.5+1.5=4.5 V

6 0

3 years ago