A 600‑kg car accelerates at a rate of 3 m/s2. How much net force is acting on the car to cause this acceleration?

Which of the following is a true statement? A. Electromagnetic waves consist of only changing electric fields. B. Electromagneti

just olya [345]

C. Electromagnetic waves don't always need a medium to travel. Note that they do vary in wavelength and frequency however their speed is fixed. Also, EM waves are always transverse and they consist of vibrating electric and magnetic fields.

7 0

4 years ago

Read 2 more answers

In a shot-put competition, a shot moving at 15m/s has 450J of mechanical kinetic energy. What is the mass of the shot? Please he

Llana [10]

Answer:

Mass of shot (m) = 4 kg

Explanation:

Given:

Velocity (v) = 15 m/s

Mechanical kinetic energy (K.E) = 450 J

Find:

Mass of shot (m) = ?

Computation:

Mechanical kinetic energy (K.E) = 1/2mv²

Mechanical kinetic energy (K.E) = [1/2](m)(15)²

450 = [1/2](m)(15)²

900 = 225 m

Mass of shot (m) = 4 kg

5 0

3 years ago

Sally runs 10,000 meter race at an average speed of 3.5m/s what does average speed mean

aleksandr82 [10.1K]

Answer:

The average speed of 3.5 m/s means that it takes Sally approximately 47.619 minutes to run 10,000 meters

Explanation:

Average speed is a scalar quantity that is given by dividing the total distance moved or traveled by an object by the time that it takes the object during the motion

The average peed indicates the rate at which the object makes a given amount of journey distance given that the journey is completed with varying speeds

With the knowledge of the average speed and the distance covered, the time for completion of the journey can be found as follows;

$Average \ speed , \overline v = \dfrac{\Delta x}{\Delta t}$

Where

$\overline v$ = Average speed of the object = 3.5 m/s

Δt = The time it takes the Sally to run 10,000 meters

Δx = The total distance Sally runs = 10,000 meters

Therefore;

$\Delta t = \dfrac{\Delta x}{ \overline v} = \dfrac{10,000 \ m}{3.5 \ m/s} = \dfrac{20,000}{7} \ s \approx 2,857.143 \ s$

The time it takes the Sally to run 10,000 meters= Δt = 20,000/7 seconds ≈ 2,857.143 seconds

20,000/7 seconds ≈ 47.619 minutes

Therefore, the average speed of 3.5 m/s means that the time it takes the Sally to run 10,000 meters ≈ 47.619 minutes

5 0

3 years ago

Bro help me

devlian [24]

Thermal energy is the sum of the energy of all the particles. That means that large objects at a low temperature (with slower moving particles) can have more energy than small objects with high temperatures (faster moving particles). The faster the particles, the more energy they can transfer.

4 0

3 years ago

a cannonball is fired with a speed of 76 m/s from the top of a cliff. It strikes the plane below with a speed of 89 m/s. if we n

galina1969 [7]

Assuming the cannonball is fired horizontally, its horizontal velocity stays at a constant 76 m/s. At the point it hits the ground, it has a speed of 89 m/s, so if its vertical velocity at that moment is $v_y$ , we have

$89\dfrac{\rm m}{\rm s}=\sqrt{\left(76\dfrac{\rm m}{\rm s}\right)^2+{v_y}^2}\implies{v_y}^2\approx2145\dfrac{\mathrm m^2}{\mathrm s^2}$

(taking the negative square root because we take the downward direction to be negative)

Recall that

${v_f}^2-{v_i}^2=2a\Delta x$

where $v_i$ and $v_f$ are the initial and final velocities, respectively; $a$ is the acceleration; and $\Delta x$ is the change in position of a body. In the cannonball's case, it starts with 0 vertical velocity and is subject to a downward acceleration with magnitude $g=9.80\frac{\rm m}{\mathrm s^2}$ . So we have

$2145\dfrac{\mathrm m^2}{\mathrm s^2}-0=-2g\Delta y\implies\Delta y\approx-109.44\,\mathrm m$

(which is negative because we take the cannonball's starting position at the top of the cliff to be the origin) so the cliff is about 109 m high.

8 0

3 years ago