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Nuetrik [128]
3 years ago
12

A powerboat, starting from rest maintains a constant acceleration. After a certain time Δt, its displacement and velocity are Δr

and Δv. At time 2Δt, what will be its displacement and velocity, assuming the acceleration remains constant?
(A) 2Δr and 2Δv
(B) 2Δr and 4Δv
(C) 4Δr and 2Δv
(D) 4Δr and 4Δv
Physics
1 answer:
Mazyrski [523]3 years ago
6 0

Answer:

The correct option is C) 4Δr and 2Δv

Explanation:

Initially from rest means , initial velocity and displacement is zero.

AT time t = Δt ,

Displacement ( s ) = Δr

velocity ( v) = Δv

Now At t = 2Δt

By using the equation of motion

v = u + at

s = ut + ( 1/2)at²

Here ,

v ∝ t   and s ∝ t²

Increasing times by two time velocity will increase twice and displacement by four times

Displacement = 4Δr

Velocity = 2Δv

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A body of mass 1kg is made to oscillate on a spring of force constant 16 n/m calculate 1 the angular frequency 2 the frequency o
Scilla [17]

Explanation:

Given that,

Mass of a body, m = 1 kg

Force constant, k = 16 N/m

We need to find the angular frequency and the frequency of oscillation.

(a) The angular frequency of a body is given by :

\omega=\sqrt{\dfrac{k}{m}} \\\\=\omega=\sqrt{\dfrac{16}{1}} \\\\=4\ rad/s

(b) The frequency of oscillation is given by :

f=\dfrac{\omega}{2\pi}\\\\f=\dfrac{4}{2\pi}\\\\=\dfrac{2}{\pi}\ Hz

Hence, this is the required solution.

7 0
2 years ago
What would happen if I removed the battery from the circuit?
ira [324]

Answer:

The current would stop

Explanation:

Electric currents are interesting because they carry little to no momentum. As soon as you remove a power source, the whole current halts.

3 0
3 years ago
If a car changes its velocity from 32 km/hr to 54 km/hr in 8.0 seconds, what is its acceleration?
Stella [2.4K]
Use the equation for the acceleration
A = final velocity - initial velocity divided by time final - time initial
A= 54 - 32 / 8 - 0
A= 22 / 8 
A= 2.75 m/s^2 
Hope this helps!
3 0
3 years ago
Read 2 more answers
a particle is moving along a circular path having a radius of 4 in such that its position as a function of time is given by thet
ANTONII [103]

Answer:

Explanation:

Given

radius of circular path r=4\ in.

Position is given by

\theta =\cos 2t---1

Differentiate 1  to angular velocity we get

\frac{\mathrm{d} \theta }{\mathrm{d} t}=\omega =-2\sin 2t----2

Differentiate 2 to get angular acceleration

\frac{\mathrm{d} \omega }{\mathrm{d} t}=-2^2\cos 2t ---3

Net acceleration is the vector summation of tangential and centripetal force

a_t=\alpha \times r

a_t=-4\cos 2t\times 4=-16\cos 2t

a_r=\omega ^2\cdot r

a_r=(-2\sin 2t)^2\cdot 4

a_r=16\sin^2(2t)

a_{net}=\sqrt{a_r^2+a_t^2}

a_{net}=\sqrt{(16\sin ^2(2t)+(-16\cos 2t)^2}

a_{net}=\sqrt{256\cos ^2(2t)+256\sin ^4(2t)}                                                    

6 0
3 years ago
A heat engine running backward is called a refrigerator if its purpose is to extract heat from a cold reservoir. The same engine
Goryan [66]

Answer:

a) 2.85 kW

b) $ 432

c) $ 76.95

Explanation:

Average price of electricity = 1 $/40 MJ

Q = 20 kW

Heat energy production = 20.0 KJ/s

Coefficient of performance,  K = 7

also

K=(QH)/Win

Now,

Coefficient of Performance, K = (QH)/Win = (QH)/P(in) = 20/P(in) = 7

where

P(in) is the input power

Thus,

P(in) = 20/7 = 2.85 kW

b) Cost = Energy consumed × charges

Cost = ($1/40000kWh) × (16kW × 300 × 3600s)

cost = $ 432

c) cost = (1$/40000kWh) × (2.85 kW × 200 × 3600s) = $76.95

4 0
3 years ago
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