Calculate kinetic and potential energy
Grade 11 Science Worksheet - Challenge Me
Circle the best answer, or write your answer on the line.
Ari's spring launcher (980 N/m) is squeezed 0.1 m and fires a 0.5 kg ball straight up. Ignoring air, how high above the launch point does it rise? Use g = 9.8 m/s².
Bo's spring launcher (490 N/m) is squeezed 0.2 m and fires a 0.5 kg ball straight up. Ignoring air, how high above the launch point does it rise? Use g = 9.8 m/s².
Esme's spring launcher (1176 N/m) is squeezed 0.1 m and fires a 0.4 kg ball straight up. Ignoring air, how high above the launch point does it rise? Use g = 9.8 m/s².
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A cart at three marks on a track (example data)
mark height above floor (m) speed (m/s) 1 1.2 2 2 0.6 3.5 3 0 4 Jun reads the table of a 2 kg cart, using g = 9.8 m/s². Between which marks is more mechanical energy removed, and how much?
- Marks 2 to 3, 16 J, the kinetic energy at the bottom
- Marks 1 to 2, 8.25 J, where the kinetic energy rises most
- Marks 2 to 3, 8.0 J, against 3.5 J from marks 1 to 2
- Neither: both stretches drop 0.6 m, so both lose the same
A drone lifts a 1.5 kg load 20 m in 25 s on 18 W of battery power. What is its efficiency, and how much energy is wasted, Kira?
- 65% efficient; it wastes 156 J
- 65% efficient; it wastes 294 J, the energy the load gained
- 35% efficient; it wastes 156 J
- 65% efficient; it wastes 6.24 J, the loss in one second
A 1.0 kg block starts 1.2 m up. Ramps A and B are 2.0 m and 6.0 m long, each with 1.0 N of friction. Which block is faster at the bottom, Luz?
- Block A: 4.4 m/s against 3.4 m/s for block B
- Block A: 4.8 m/s against 3.4 m/s for block B
- Block B: 4.4 m/s against 3.4 m/s for block A
- Tie at 4.8 m/s, since both drop 1.2 m
A spring's stored energy (example data)
stretch (cm) stored energy (J) 2 0.4 4 1.6 6 3.6 Milo says a spring stretched twice as far stores twice the energy. Does the table support the claim?
- Yes: stretch and energy rise together, so they are proportional
- No: the stretch doubles but the energy becomes 8 times as large
- Yes: 4 cm is twice 2 cm, and 1.6 J is about twice 0.4 J
- No: 2 cm to 4 cm takes the energy from 0.4 J to 1.6 J, 4 times
Two balls (example data)
ball mass (kg) speed (m/s) ball P 1 2 ball Q 0.2 8 Noah says the heavier ball always has more kinetic energy. Which reply fits the table?
- No: ball Q has 12.8 J against 4 J, because energy is mass times speed squared
- No: ball Q has 6.4 J against ball P's 2 J, because speed is squared
- No: the two balls have equal energy, 2 J each
- Yes: ball P has 2 J against 1.6 J for ball Q
Pia says a 5 kg box at 0 J of gravitational energy on a table top gains no kinetic energy falling 0.8 m to the floor. Use g = 9.8 m/s². Reply?
- Yes: its gravitational energy is 0 J, so nothing can become motion
- No: it loses 39.2 J of gravitational energy, which becomes motion
- Yes: the floor is the zero level, so it has no energy there
- No: it loses 4 J of gravitational energy, 5 × 0.8
A 1.0 kg mass on a string over a pulley pulls a 3.0 kg cart across a smooth table. After falling 0.80 m from rest, how fast is the cart, Tala?
- 3.96 m/s: ½ × 1.0 × v² = 7.84
- 2.29 m/s: ½ × 3.0 × v² = 7.84
- 1.98 m/s: v² = 2 × 7.84 ÷ 4.0
- 1.40 m/s: 1.0 × v² = 7.84 ÷ 4.0