4 years ago

Help me please!! 15points

Physics

1 answer:

Romashka-Z-Leto [24]4 years ago

4 0

Explanation:

Acceleration is the change in speed over change in time.

a = Δv / Δt

a. The car's acceleration is:

a = (80 km/h − 0 km/h) / 10 s

a = 8 km/h/s

So every second, the speed increases by 8 km/h.

b. The cyclist's acceleration is:

a = (16 m/s − 4.0 m/s) / 5.6 s

a = 2.1 m/s²

c. The stone's speed is:

10.0 m/s² = (v − 0 m/s) / 3.5 s

v = 35 m/s

d. The time is:

1.6 m/s² = (10 m/s − 0 m/s) / t

t = 6.3 s

You might be interested in

A rock dropped down a well takes 1.8 s to hit the water. How far below the top of the well is the surface of the water

Brut [27]

Answer: 15.87 m

From the equation of motion:

$s=ut+\frac{1}{2}at^2$

where, $s$ is the distance traveled, $u$ is the initial velocity, $a$ is the acceleration and $t$ is the time.

The rock free falls under gravity. Initial velocity, $u=0 m/s$ , $a=g=9.8m/s^2$

It took $t=1.8 s$ for rock to hit the water.

Substitute the values in the given equation:

$\Rightarrow s=0+\frac{1}{2}9.8m/s^2\times(1.8s)^2=15.87 m$

Hence, the water is 15.87 m below the top level of the well.

3 0

4 years ago

The north and south poles of a magnetic field produced by an electromagnet will switch when the direction of the changes.

Aneli [31]

When the direction of the current changes

3 0

3 years ago

Read 2 more answers

A 36 kg child sits in a swing supported by two chains, each 2.9 m long. If the tension in each chain at the lowest point is 265

natka813 [3]

Answer:

v = 3.78 m/s

Explanation:

given,

mass of the child = 36 Kg

length of the chain, r = 2.9 m

tension in each chain, T = 265 N

now,

Net force acting in the system

2 T - m g = m a

T is the tension in the chain

a is the acceleration in the normal direction

here, $a = \dfrac{v^2}{r}$

now,

$2 T - m g = m\dfrac{v^2}{r}$

$2\times 265 - 36\times 9.8 = 36\times \dfrac{v^2}{2.9}$

v² = 14.274

v = 3.78 m/s

speed of the child at the lowest point is equal to 3.78 m/s

5 0

3 years ago

What property appplies to the element radon?

Arlecino [84]

Radioactive element
I. E..,ratio of neutrons is to protons is greater than 1.5

8 0

3 years ago

What is the kinetic energy of a 478 kg object that is moving with the speed of 15 m/s

Tpy6a [65]

Kinetic energy = (1/2)*mass*velocity^2
KE = (1/2)mv^2
KE = (1/2)(478)(15)^2
KE = 53775J

5 0

3 years ago