Apply conservation of energy; the pendulum's maximum potential energy (at the highest point of its motion) equals the maximum kinetic energy (at the lowest point of its motion):
Max PE = Max KE
We will calculate the max PE, ie the potential energy after that ball is lifted up:
Max PE = mgh
PE is the potential energy, m is the ball's mass, g is acceleration due to earth's gravity, and h is the height.
Given values:
m = 2kg
g = 9.81m/s²
h = 1.5m
Plug in the values and solve for Max PE:
Max PE = 2(9.81)(1.5)
Max PE = 29.43J
The ball's kinetic energy is given by:
KE = 0.5mv²
We know the ball's velocity is greatest when it attains Max KE, and the max KE equals the Max PE:
Max KE = Max PE = 29.43J = 0.5mv²
Given values:
m = 2kg
Now plug in and solve for v:
2v² = 58.86
v = 5.425
v = 5.4m/s
1,4,6
a bow is drawn back
a gun is loaded w/ a dart
a bungee cord is stretched
All it really is is velocity.
<span>When it hits the pin, momentum is conserved and the pin is sent flying. The ball continues to roll with reduced kinetic energy. </span>
A bodybuilder deadlifts 215 kg to a height of 0.90 m. If he deadlifts this weight 10 times in 45 s, the power exerted is 421 W (b.)
<h3>What is power?</h3>
In physics, power (P) is the work (W) done over a period of time.
- Step 1. Calculate the work done by the bodybuilder each time.
The bodybuilder lifts a 215 kg (m) weight to a height of 0.90 m (h). Being the gravity (g) of 9.81 m/s², we can calculate the work done in each lift using the following expression.
W = m × g × h = 215 kg × 9.81 m/s² × 0.90 m = 1.9 × 10³ N
- Step 2. Calculate the work done by the bodybuilder over 10 times.
W = 10 × 1.9 × 10³ N = 1.9 × 10⁴ N
- Step 3. Calculate the power exerted by the bodybuilder.
The bodybuilder does a work of 1.9 × 10⁴ N in a 45-s span.
P = 1.9 × 10⁴ N/45 s = 421 W
A bodybuilder deadlifts 215 kg to a height of 0.90 m. If he deadlifts this weight 10 times in 45 s, the power exerted is 421 W (b.)
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Answer:
= 0.7 A, = 1.3 A and ε = 7.4 V
Explanation:
From the given circuit, applying Kirchhoff's rule;
Ammeter reading, = 2 A
⇒ = + = 2 A
Dividing the circuit to loops 1 and 2.
a. From loop 1,
15 + 7 - 5 = 0
15 + 7 - 10 = 0 (since = 2 A)
7 - 5 = 0
= 0.7 A
But, = +
⇒ 2 = 0.7 +
= 1.3 A
b. From loop 2,
ε + 2 - 5 = 0
ε + 2 - 10 = 0
ε + 2.6 - 10 = 0
ε - 7.4 = 0
ε = 7.4 V
Therefore, = 0.7 A, = 1.3 A and ε = 7.4 V.