All categories

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

Now assume that the pitcher in Part D throws a 0.145-kg baseball parallel to the ground with a speed of 32 m/s in the +x directi

pogonyaev

Answer:

V2 = -25.93 m/s

Explanation:

First of all, we know that;

Momentum = mass x change in velocity

Thus;

Momentum = m(v2 - v1)

Also, we know that;

Impulse = force x time

And also that;

Momentum = Impulse

From the question, m = 0.145kg and V1 = 32m/s while impulse = -8.4 N.s

Thus;

0.145(v2 - 32) = -8.4

Now,

0.145v2 - 4.64 = -8.4

0.145v2 = -8.4 + 4.64

0.145v2 = -3.76

v2 = -3.76/0.145

= -25.931 m/s and to two significant figures gives -25.93 m/s

7 0

3 years ago

zanele has a mass of 40kg and is sitting inside a 20kg cart .zanele's friends pull a cart with a force of 500N at an angle of 20

Dmitriy789 [7]

The net horizontal force acting on the cart is 169.85 N.

The change in the carts momentum is 5,000 Ns.

The net horizontal force on Zanele is same as the net horizontal force on the cart.

If angle between the 500N force and the horizontal is decreased, the final velocity of the cart increases.

The given parameters:

Mass of zanele, m1 = 40 kg
Mass of the cart, m2 = 20 kg
Applied force, F = 500 N, at angle 20 degrees
Frictional force on the cart, Ff = 300 N
Time, t = 10 s

<h3>Net horizontal force on the cart;</h3>

The net horizontal force acting on the cart is calculated as follows;

$F_{net} = F - F_f\\\\F_{net} = 500 \times cos(20) - 300\\\\F_{net} = 169.85 \ N$

<h3>Change in momentum;</h3>

The change in the carts momentum at the given time of applied force is calculated as follows;

$\Delta mv = Ft \\\\\Delta mv = 500 \times 10= 5,000 \ Ns$

The net horizontal force on Zanele is same as the net horizontal force on the cart.

<h3>The final velocity of the cart;</h3>

When the angle decreases the cart's final velocity would be affected as follows;

$F_{net} = F - F_f\\\\F_{net} = \frac{mv}{t} \\\\\frac{mv}{t} = F - F_f\\\\ \frac{mv}{t} = Fcos(\theta) - F_f\\\\let \ \theta = 0^0\\\\\frac{mv}{t} =500 \times cos(0) - 300\\\\\frac{mv}{t} = 200\\\\v = \frac{200 t}{m} \\\\when \ \theta = 20^0\\\\\frac{mv}{t} =500 \times cos(20) - 300\\\\\frac{mv}{t} = 169.85\\\\v = \frac{169.85t}{m}$

Thus, if angle between the 500N force and the horizontal is decreased, the final velocity of the cart increases.

Learn more about net horizontal force here: brainly.com/question/21684583

5 0

3 years ago

A cart, which has a mass of m - 2.50 kg, is sitting at the top of an inclined plane which is 3.30 meters long and which meets th

SashulF [63]

Answer:

Part(i) the time taken for this cart to reach the bottom of the inclined plane is 1.457 s

Part(ii) the velocity of the cart when it reaches the bottom of the inclined plane is 4.531 m/s

Part(iii) the kinetic energy of the cart when it reaches the bottom of the inclined plane is 25.663 J

Explanation:

Given;

mass of the cart = 2.5 kg

angle of inclination, β = 18.5⁰

length of inclined plane = 3.3m

Part(i) the time taken for this cart to reach the bottom of the inclined plane

s = ut + ¹/₂×at²

initial vertical velocity, u = 0

s = 3.3 m

s = ¹/₂×at²

$t = \sqrt{\frac{2s}{a} }$

acceleration, of the cart, a = gsinβ

a = 9.8sin(18.5) = 3.11 m/s²

$t = \sqrt{\frac{2X3.3}{3.11 }}= 1.457 s$

Part(ii) the velocity of the cart when it reaches the bottom of the inclined plane

V = a×t

V = 3.11 × 1.457 = 4.531 m/s

Part(iii) the kinetic energy of the cart when it reaches the bottom of the inclined plane

KE = ¹/₂MV²

= ¹/₂ × 2.5× (4.531)²

= 25.663 J

6 0

4 years ago

Some one please help me

sattari [20]

Seal the roof and remove the moisture. Mold cannot survive in a dry environment so this will help remove it in an ecologically fiend way.

3 0

3 years ago

If the coefficient of kinetic friction between a crate and the floor is 0.20,

kow [346]

Answer:

0.3 newtons

Explanation:

4 0

3 years ago