19 dm expressed in millimeters

What are three ways a driver can cause a car to accelerate?

algol13

If you have to pick 3 answers then B, C, and D but if you pick only 1 answer then pick D

8 0

3 years ago

A car drives over a hilltop that has a radius of curvature 0.120 km at the top of the hill. At what speed would the car be trave

Mashutka [201]

Answer:

34.3 m/s

Explanation:

Newton's Second Law states that the resultant of the forces acting on the car is equal to the product between the mass of the car, m, and the centripetal acceleration $a_c$ (because the car is moving of circular motion). So at the top of the hill the equation of the forces is:

$mg-R = m a_c = m\frac{v^2}{r}$

where

(mg) is the weight of the car (downward), with m being the car's mass and g=9.8 m/s^2 is the acceleration due to gravity

R is the normal reaction exerted by the road on the car (upward, so with negative sign)

v is the speed of the car

r = 0.120 km = 120 m is the radius of the curve

The problem is asking for the speed that the car would have when it tires just barely lose contact with the road: this means requiring that the normal reaction is zero, R=0. Substituting into the equation and solving for v, we find:

$v=\sqrt{gr}=\sqrt{(9.8 m/s^2)(120 m)}=34.3 m/s$

6 0

3 years ago

Sound waves travel in air at 343 m/s. The lowest frequency one can hear is 25.0 Hz; the highest frequency is 25.0 kHz. Find the

Slav-nsk [51]

Answer:

13.72 m and 0.01372 m respectively

Explanation:

Wavelength: This can be defined as the distance covered in one complete oscillation. The S.I unit of wavelength is meter (m).

The formula for the speed of a wave is given as

v = λf ............................. Equation 1

Where v = speed of the sound wave, λ = wavelength, f = frequency of the sound wave.

make λ the subject of the equation,

λ = v/f ......................... Equation 2

For the lowest frequency,

Given: f = 25 Hz, v = 343 m/s.

Substitute into equation 2

λ = 343/25

λ = 13.72 m.

For the highest frequency,

Given: f = 25 kHz = 25000 Hz, v = 343 m/s

Substitute into equation 2

λ = 343/25000

λ = 0.01372 m.

The wavelength of sound for 25 Hz and 25 kHz = 13.72 m and 0.01372 m respectively

8 0

3 years ago

Two astronauts push on a satellite. One pushes in the positive x direction with a force of 42 N, and the other pushes in the pos

inessss [21]

The vectors adition we can find the magnitude of the force applied by the other astronaut is 11.25 N in the y direction

Parameters given

Force of an astronaut Fₓ = 42 N

Angle θ = 15º

To find

Force another astronaut

The force is a vector magnitude for which the addition of vectors must be used, a very efficient method to perform this sum is to add the components of each vector and devise constructing the resulting vector using trigonometry and the Pythagorean theorem.

Let's use trigonometry to find the other force

tan θ = $\frac{F_y}{F_x}$