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3 years ago

Can someone please help me with these 2 questions

1 answer:

5 0

1. Answer: 7.75 seconds
Explanation: 76-14=62 metres
62/8=7.75 seconds

2. Answer: 2.5 seconds
Explanation: 28-18=10 metres
10/4=2.5 seconds

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On a horizontal frictionless surface, a small block with mass 0.200 kg has a collision with a block of mass 0.400 kg. Immediatel

Akimi4 [234]

Answer:48.2 Joules

Explanation:

Given

two masses of 0.2 kg and 0.4 kg collide with each other

after collision 0.2 kg deflect 30 north of east and 0.4 kg deflects 53.1 south of east

Velocity of 0.2 kg mass is

$v_{0.2}=12\cos (30)\hat{i}+12\sin (30)\hat{j}$

$|v_{0.2}|=11.99 m/s\approx 12 m/s$

Velocity of 0.4 kg mass

$v_{0.4}=13\cos (53.1)\hat{i}-12\sin (53.1)\hat{j}$

$|v_{0.4}|=12.99 m/s\approx 13 m/s$

Thus total Kinetic energy $=\frac{0.2\times 12^2}{2}+\frac{0.4\times 13^2}{2}$

Kinetic energy=48.2 J

8 0

2 years ago

A disk-shaped grindstone of mass 3.0 kg and radius 8.0 cm is spinning at 600 rev/min. After the power is shut off, a man continu

kolbaska11 [484]

Answer:

τ=0.060 N.m

Explanation:

By kinematics:

$\omega f = \omega o-\alpha*t$

Solving for α:

$\alpha=\frac{\omega o-\omega f}{t}$

where ωo = 600*2*π/60; ωf = 0; t=10s

$\alpha=6.283rad/s^2$

The sum of torque is:

$\tau=I*\alpha$

$\tau=M*R^2/2*\alpha$

$\tau=0.060 N.m$

8 0

3 years ago

A passenger bus is travelling 28.0 m/s to the right when the driver applies the brakes. The bus stops in 5.00 s. What is the acc

MAVERICK [17]

Change in velocity = d(v)
d(v) = v2 - v1 where v1 = initial speed, v2 = final speed
v1 = 28.0 m/s to the right
v2 = 0.00 m/s
d(v) = (0 - 28)m/s = -28 m/s to the right

Change in time = d(t)
d(t) = t2 - t1 where t1 = initial elapsed time, t2 = final elapsed time
t1 = 0.00 s
t2 = 5.00 s
d(t) = (5.00 - 0.00)s = 5.00s

Average acceleration = d(v) / d(t)
(-28.0 m/s) / (5.00 s)
(-28.0 m)/s * 1 / (5.00 s) = -5.60 m/s² to the right

3 0

2 years ago

Read 2 more answers

Marina walked 2km in half an hour, what was her average speed during her walk?

ad-work [718]

Answer:

4km/hr

Explanation:

6 0

2 years ago

Calculate the maximum absolute uncertainty for R if:

Radda [10]

Answer:

ΔR = 9 s

Explanation:

To calculate the propagation of the uncertainty or absolute error, the variation with each parameter must be calculated and the but of the cases must be found, which is done by taking the absolute value

The given expression is R = 2A / B

the uncertainty is ΔR = | $\frac{dR}{dA}$ | ΔA + | $\frac{ dR}{dB}$ | ΔB