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Hingga ujian berikutnya 14–15 November 2026:
Semua konsep

Work and Power

功和功率

The defining equation for work done by a constant force and the sign convention, total work done by several forces, and average versus instantaneous power.

11 soal ujian asli · 4 kali ujian21 soal tryout13 soal latihan

Ujian CSCA dikerjakan dalam bahasa Mandarin atau Inggris — peserta memilih sendiri. Karena itu konsep dan rumus di sini disajikan dalam kedua bahasa tersebut; halaman ini menampilkan versi bahasa Inggris.

Rumus

  • Work done by a constant force

    Definisi
    W=Fscos⁡θW=Fs\cos\theta

    Berlaku bila：θ is the angle between force and displacement; work is negative when θ>90°

  • Definition of power

    Definisi
    P=WtP=\frac{W}{t}

    Berlaku bila：Gives the average power over that interval

  • Power in terms of force and velocity

    Rumus
    P=Fvcos⁡θP=Fv\cos\theta

    Berlaku bila：Instantaneous v gives instantaneous power; average v gives average power

Cara ujian sebenarnya menguji konsep ini

Soal dari ujian CSCA sebenarnya yang menguji konsep ini. Kerjakan sendiri dulu sebelum membuka jawabannya.

  1. CSCA Physics December 2025 Past Paper
    A horizontal pulling force F of 20 N is applied to an object of mass 10 kg . The object moves 5 m on a rough horizontal surface with a friction force f=5 Nf = 5 \mathrm {~N}. The work done by the pulling force FF is ( ).
    • A．100 J
    • B．75 J
    • C．- 25 J
    • D．25 J
    Lihat jawaban & pembahasan

    Jawaban: A

    1 Work by the pulling force: W=Fscos⁡0=20 N×5 m=100 JW = F s \cos 0 = 20 \mathrm {~N} \times 5 \mathrm {~m} = 100 \mathrm {~J}.
    Lihat di CSCA Physics December 2025 Past Paper lengkap
  2. CSCA Physics March 2026 Past Paper
    A horizontal force F pulls an object 5 m , doing 50 J of work. F equals
    • A．5 N
    • B．10 N
    • C．15 N
    • D．20 N
    Lihat jawaban & pembahasan

    Jawaban: B

    W=FsW = F s (same direction, cos⁡0∘=1)\left. \cos 0 ^ { \circ } = 1 \right) . F=50/5=10 NF = 50 / 5 = 10 \mathrm {~N}. Answer: BB.
    Kerjakan CSCA Physics March 2026 Past Paper lengkap — berwaktu & dinilai
  3. CSCA Physics April 2026 Past Paper
    As shown in the figure, a tower crane uses a steel cable to lift a load of mass mm vertically with acceleration aa through a height hh. The gravitational acceleration is gg. Which statement about this process is correct? Question 45 diagram
    • A．Work done by the cable tension is m(a+g)hm ( a + g ) h
    • B．Work done by gravity on the load is - mah
    • C．Work done by the net force on the load is mghm g h
    • D．The load's gravitational potential energy decreases by mghm g h
    Lihat jawaban & pembahasan

    Jawaban: A

    Newton's second law in the vertical direction: T−mg=ma⇒T=m(g+a)T - m g = m a \Rightarrow T = m ( g + a ). (A) WT=T⋅h=m(g+a)hW _ { T } = T \cdot h = m ( g + a ) h - correct ✓\checkmark. (B) Gravity does negative work: WG=−mghW _ { G } = - m g h, not - mah - wrong. (C) Net-force work: Wnet =(T−mg)h=mahW _ { \text {net } } = ( T - m g ) h = m a h, not mghm g h - wrong. (D) The load rises by hh, so gravitational PE increases by mghm g h (not decreases) - wrong.
    Kerjakan CSCA Physics April 2026 Past Paper lengkap — berwaktu & dinilai

Bukti dari ujian asli

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11 soal dari 4 kali ujian1/4 ujian dapat diverifikasi gratis secara online

21 soal dari 6 paket tryout — paket buatan kami sendiri, jadi ini sinyal cakupan, bukan bukti ujian asli

Tersedia 13 soal latihan terkaitLatihan gratis: Usaha dan Energi

Bukti ujian asli berasal dari arsip ujian CSCA yang tercatat; soal yang naskah aslinya hilang dikecualikan, dan paket sprint sengaja tidak dihitung.

Konsep terkait

Kinetic Energy and the Work–Energy TheoremConservation of Mechanical Energy